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// Astring is a tiny and fast JavaScript code generator from an ESTree-compliant AST.
//
// Astring was written by David Bonnet and released under an MIT license.
//
// The Git repository for Astring is available at:
// https://github.com/davidbonnet/astring.git
//
// Please use the GitHub bug tracker to report issues:
// https://github.com/davidbonnet/astring/issues
const { stringify } = JSON
/* c8 ignore if */
if (!String.prototype.repeat) {
/* c8 ignore next */
throw new Error(
'String.prototype.repeat is undefined, see https://github.com/davidbonnet/astring#installation',
)
}
/* c8 ignore if */
if (!String.prototype.endsWith) {
/* c8 ignore next */
throw new Error(
'String.prototype.endsWith is undefined, see https://github.com/davidbonnet/astring#installation',
)
}
const OPERATOR_PRECEDENCE = {
'||': 3,
'&&': 4,
'|': 5,
'^': 6,
'&': 7,
'==': 8,
'!=': 8,
'===': 8,
'!==': 8,
'<': 9,
'>': 9,
'<=': 9,
'>=': 9,
in: 9,
instanceof: 9,
'<<': 10,
'>>': 10,
'>>>': 10,
'+': 11,
'-': 11,
'*': 12,
'%': 12,
'/': 12,
'**': 13,
}
// Enables parenthesis regardless of precedence
export const NEEDS_PARENTHESES = 17
export const EXPRESSIONS_PRECEDENCE = {
// Definitions
ArrayExpression: 20,
TaggedTemplateExpression: 20,
ThisExpression: 20,
Identifier: 20,
Literal: 18,
TemplateLiteral: 20,
Super: 20,
SequenceExpression: 20,
// Operations
MemberExpression: 19,
ChainExpression: 19,
CallExpression: 19,
NewExpression: 19,
// Other definitions
ArrowFunctionExpression: NEEDS_PARENTHESES,
ClassExpression: NEEDS_PARENTHESES,
FunctionExpression: NEEDS_PARENTHESES,
ObjectExpression: NEEDS_PARENTHESES,
// Other operations
UpdateExpression: 16,
UnaryExpression: 15,
AwaitExpression: 15,
BinaryExpression: 14,
LogicalExpression: 13,
ConditionalExpression: 4,
AssignmentExpression: 3,
YieldExpression: 2,
RestElement: 1,
}
function formatSequence(state, nodes) {
/*
Writes into `state` a sequence of `nodes`.
*/
const { generator } = state
state.write('(')
if (nodes != null && nodes.length > 0) {
generator[nodes[0].type](nodes[0], state)
const { length } = nodes
for (let i = 1; i < length; i++) {
const param = nodes[i]
state.write(', ')
generator[param.type](param, state)
}
}
state.write(')')
}
function expressionNeedsParenthesis(state, node, parentNode, isRightHand) {
const nodePrecedence = state.expressionsPrecedence[node.type]
if (nodePrecedence === NEEDS_PARENTHESES) {
return true
}
const parentNodePrecedence = state.expressionsPrecedence[parentNode.type]
if (nodePrecedence !== parentNodePrecedence) {
// Different node types
return (
(!isRightHand &&
nodePrecedence === 15 &&
parentNodePrecedence === 14 &&
parentNode.operator === '**') ||
nodePrecedence < parentNodePrecedence
)
}
if (nodePrecedence !== 13 && nodePrecedence !== 14) {
// Not a `LogicalExpression` or `BinaryExpression`
return false
}
if (node.operator === '**' && parentNode.operator === '**') {
// Exponentiation operator has right-to-left associativity
return !isRightHand
}
if (isRightHand) {
// Parenthesis are used if both operators have the same precedence
return (
OPERATOR_PRECEDENCE[node.operator] <=
OPERATOR_PRECEDENCE[parentNode.operator]
)
}
return (
OPERATOR_PRECEDENCE[node.operator] <
OPERATOR_PRECEDENCE[parentNode.operator]
)
}
function formatExpression(state, node, parentNode, isRightHand) {
/*
Writes into `state` the provided `node`, adding parenthesis around if the provided `parentNode` needs it. If `node` is a right-hand argument, the provided `isRightHand` parameter should be `true`.
*/
const { generator } = state
if (expressionNeedsParenthesis(state, node, parentNode, isRightHand)) {
state.write('(')
generator[node.type](node, state)
state.write(')')
} else {
generator[node.type](node, state)
}
}
function reindent(state, text, indent, lineEnd) {
/*
Writes into `state` the `text` string reindented with the provided `indent`.
*/
const lines = text.split('\n')
const end = lines.length - 1
state.write(lines[0].trim())
if (end > 0) {
state.write(lineEnd)
for (let i = 1; i < end; i++) {
state.write(indent + lines[i].trim() + lineEnd)
}
state.write(indent + lines[end].trim())
}
}
function formatComments(state, comments, indent, lineEnd) {
/*
Writes into `state` the provided list of `comments`, with the given `indent` and `lineEnd` strings.
Line comments will end with `"\n"` regardless of the value of `lineEnd`.
Expects to start on a new unindented line.
*/
const { length } = comments
for (let i = 0; i < length; i++) {
const comment = comments[i]
state.write(indent)
if (comment.type[0] === 'L') {
// Line comment
state.write('// ' + comment.value.trim() + '\n', comment)
} else {
// Block comment
state.write('/*')
reindent(state, comment.value, indent, lineEnd)
state.write('*/' + lineEnd)
}
}
}
function hasCallExpression(node) {
/*
Returns `true` if the provided `node` contains a call expression and `false` otherwise.
*/
let currentNode = node
while (currentNode != null) {
const { type } = currentNode
if (type[0] === 'C' && type[1] === 'a') {
// Is CallExpression
return true
} else if (type[0] === 'M' && type[1] === 'e' && type[2] === 'm') {
// Is MemberExpression
currentNode = currentNode.object
} else {
return false
}
}
}
function formatVariableDeclaration(state, node) {
/*
Writes into `state` a variable declaration.
*/
const { generator } = state
const { declarations } = node
state.write(node.kind + ' ')
const { length } = declarations
if (length > 0) {
generator.VariableDeclarator(declarations[0], state)
for (let i = 1; i < length; i++) {
state.write(', ')
generator.VariableDeclarator(declarations[i], state)
}
}
}
let ForInStatement,
FunctionDeclaration,
RestElement,
BinaryExpression,
ArrayExpression,
BlockStatement
export const GENERATOR = {
/*
Default generator.
*/
Program(node, state) {
const indent = state.indent.repeat(state.indentLevel)
const { lineEnd, writeComments } = state
if (writeComments && node.comments != null) {
formatComments(state, node.comments, indent, lineEnd)
}
const statements = node.body
const { length } = statements
for (let i = 0; i < length; i++) {
const statement = statements[i]
if (writeComments && statement.comments != null) {
formatComments(state, statement.comments, indent, lineEnd)
}
state.write(indent)
this[statement.type](statement, state)
state.write(lineEnd)
}
if (writeComments && node.trailingComments != null) {
formatComments(state, node.trailingComments, indent, lineEnd)
}
},
BlockStatement: (BlockStatement = function (node, state) {
const indent = state.indent.repeat(state.indentLevel++)
const { lineEnd, writeComments } = state
const statementIndent = indent + state.indent
state.write('{')
const statements = node.body
if (statements != null && statements.length > 0) {
state.write(lineEnd)
if (writeComments && node.comments != null) {
formatComments(state, node.comments, statementIndent, lineEnd)
}
const { length } = statements
for (let i = 0; i < length; i++) {
const statement = statements[i]
if (writeComments && statement.comments != null) {
formatComments(state, statement.comments, statementIndent, lineEnd)
}
state.write(statementIndent)
this[statement.type](statement, state)
state.write(lineEnd)
}
state.write(indent)
} else {
if (writeComments && node.comments != null) {
state.write(lineEnd)
formatComments(state, node.comments, statementIndent, lineEnd)
state.write(indent)
}
}
if (writeComments && node.trailingComments != null) {
formatComments(state, node.trailingComments, statementIndent, lineEnd)
}
state.write('}')
state.indentLevel--
}),
ClassBody: BlockStatement,
EmptyStatement(node, state) {
state.write(';')
},
ExpressionStatement(node, state) {
const precedence = state.expressionsPrecedence[node.expression.type]
if (
precedence === NEEDS_PARENTHESES ||
(precedence === 3 && node.expression.left.type[0] === 'O')
) {
// Should always have parentheses or is an AssignmentExpression to an ObjectPattern
state.write('(')
this[node.expression.type](node.expression, state)
state.write(')')
} else {
this[node.expression.type](node.expression, state)
}
state.write(';')
},
IfStatement(node, state) {
state.write('if (')
this[node.test.type](node.test, state)
state.write(') ')
this[node.consequent.type](node.consequent, state)
if (node.alternate != null) {
state.write(' else ')
this[node.alternate.type](node.alternate, state)
}
},
LabeledStatement(node, state) {
this[node.label.type](node.label, state)
state.write(': ')
this[node.body.type](node.body, state)
},
BreakStatement(node, state) {
state.write('break')
if (node.label != null) {
state.write(' ')
this[node.label.type](node.label, state)
}
state.write(';')
},
ContinueStatement(node, state) {
state.write('continue')
if (node.label != null) {
state.write(' ')
this[node.label.type](node.label, state)
}
state.write(';')
},
WithStatement(node, state) {
state.write('with (')
this[node.object.type](node.object, state)
state.write(') ')
this[node.body.type](node.body, state)
},
SwitchStatement(node, state) {
const indent = state.indent.repeat(state.indentLevel++)
const { lineEnd, writeComments } = state
state.indentLevel++
const caseIndent = indent + state.indent
const statementIndent = caseIndent + state.indent
state.write('switch (')
this[node.discriminant.type](node.discriminant, state)
state.write(') {' + lineEnd)
const { cases: occurences } = node
const { length: occurencesCount } = occurences
for (let i = 0; i < occurencesCount; i++) {
const occurence = occurences[i]
if (writeComments && occurence.comments != null) {
formatComments(state, occurence.comments, caseIndent, lineEnd)
}
if (occurence.test) {
state.write(caseIndent + 'case ')
this[occurence.test.type](occurence.test, state)
state.write(':' + lineEnd)
} else {
state.write(caseIndent + 'default:' + lineEnd)
}
const { consequent } = occurence
const { length: consequentCount } = consequent
for (let i = 0; i < consequentCount; i++) {
const statement = consequent[i]
if (writeComments && statement.comments != null) {
formatComments(state, statement.comments, statementIndent, lineEnd)
}
state.write(statementIndent)
this[statement.type](statement, state)
state.write(lineEnd)
}
}
state.indentLevel -= 2
state.write(indent + '}')
},
ReturnStatement(node, state) {
state.write('return')
if (node.argument) {
state.write(' ')
this[node.argument.type](node.argument, state)
}
state.write(';')
},
ThrowStatement(node, state) {
state.write('throw ')
this[node.argument.type](node.argument, state)
state.write(';')
},
TryStatement(node, state) {
state.write('try ')
this[node.block.type](node.block, state)
if (node.handler) {
const { handler } = node
if (handler.param == null) {
state.write(' catch ')
} else {
state.write(' catch (')
this[handler.param.type](handler.param, state)
state.write(') ')
}
this[handler.body.type](handler.body, state)
}
if (node.finalizer) {
state.write(' finally ')
this[node.finalizer.type](node.finalizer, state)
}
},
WhileStatement(node, state) {
state.write('while (')
this[node.test.type](node.test, state)
state.write(') ')
this[node.body.type](node.body, state)
},
DoWhileStatement(node, state) {
state.write('do ')
this[node.body.type](node.body, state)
state.write(' while (')
this[node.test.type](node.test, state)
state.write(');')
},
ForStatement(node, state) {
state.write('for (')
if (node.init != null) {
const { init } = node
if (init.type[0] === 'V') {
formatVariableDeclaration(state, init)
} else {
this[init.type](init, state)
}
}
state.write('; ')
if (node.test) {
this[node.test.type](node.test, state)
}
state.write('; ')
if (node.update) {
this[node.update.type](node.update, state)
}
state.write(') ')
this[node.body.type](node.body, state)
},
ForInStatement: (ForInStatement = function (node, state) {
state.write(`for ${node.await ? 'await ' : ''}(`)
const { left } = node
if (left.type[0] === 'V') {
formatVariableDeclaration(state, left)
} else {
this[left.type](left, state)
}
// Identifying whether node.type is `ForInStatement` or `ForOfStatement`
state.write(node.type[3] === 'I' ? ' in ' : ' of ')
this[node.right.type](node.right, state)
state.write(') ')
this[node.body.type](node.body, state)
}),
ForOfStatement: ForInStatement,
DebuggerStatement(node, state) {
state.write('debugger;', node)
},
FunctionDeclaration: (FunctionDeclaration = function (node, state) {
state.write(
(node.async ? 'async ' : '') +
(node.generator ? 'function* ' : 'function ') +
(node.id ? node.id.name : ''),
node,
)
formatSequence(state, node.params)
state.write(' ')
this[node.body.type](node.body, state)
}),
FunctionExpression: FunctionDeclaration,
VariableDeclaration(node, state) {
formatVariableDeclaration(state, node)
state.write(';')
},
VariableDeclarator(node, state) {
this[node.id.type](node.id, state)
if (node.init != null) {
state.write(' = ')
this[node.init.type](node.init, state)
}
},
ClassDeclaration(node, state) {
state.write('class ' + (node.id ? `${node.id.name} ` : ''), node)
if (node.superClass) {
state.write('extends ')
const { superClass } = node
const { type } = superClass
const precedence = state.expressionsPrecedence[type]
if (
(type[0] !== 'C' || type[1] !== 'l' || type[5] !== 'E') &&
(precedence === NEEDS_PARENTHESES ||
precedence < state.expressionsPrecedence.ClassExpression)
) {
// Not a ClassExpression that needs parentheses
state.write('(')
this[node.superClass.type](superClass, state)
state.write(')')
} else {
this[superClass.type](superClass, state)
}
state.write(' ')
}
this.ClassBody(node.body, state)
},
ImportDeclaration(node, state) {
state.write('import ')
const { specifiers } = node
const { length } = specifiers
// TODO: Once babili is fixed, put this after condition
// https://github.com/babel/babili/issues/430
let i = 0
if (length > 0) {
for (; i < length; ) {
if (i > 0) {
state.write(', ')
}
const specifier = specifiers[i]
const type = specifier.type[6]
if (type === 'D') {
// ImportDefaultSpecifier
state.write(specifier.local.name, specifier)
i++
} else if (type === 'N') {
// ImportNamespaceSpecifier
state.write('* as ' + specifier.local.name, specifier)
i++
} else {
// ImportSpecifier
break
}
}
if (i < length) {
state.write('{')
for (;;) {
const specifier = specifiers[i]
const { name } = specifier.imported
state.write(name, specifier)
if (name !== specifier.local.name) {
state.write(' as ' + specifier.local.name)
}
if (++i < length) {
state.write(', ')
} else {
break
}
}
state.write('}')
}
state.write(' from ')
}
this.Literal(node.source, state)
state.write(';')
},
ImportExpression(node, state) {
state.write('import(')
this[node.source.type](node.source, state)
state.write(')')
},
ExportDefaultDeclaration(node, state) {
state.write('export default ')
this[node.declaration.type](node.declaration, state)
if (
state.expressionsPrecedence[node.declaration.type] != null &&
node.declaration.type[0] !== 'F'
) {
// All expression nodes except `FunctionExpression`
state.write(';')
}
},
ExportNamedDeclaration(node, state) {
state.write('export ')
if (node.declaration) {
this[node.declaration.type](node.declaration, state)
} else {
state.write('{')
const { specifiers } = node,
{ length } = specifiers
if (length > 0) {
for (let i = 0; ; ) {
const specifier = specifiers[i]
const { name } = specifier.local
state.write(name, specifier)
if (name !== specifier.exported.name) {
state.write(' as ' + specifier.exported.name)
}
if (++i < length) {
state.write(', ')
} else {
break
}
}
}
state.write('}')
if (node.source) {
state.write(' from ')
this.Literal(node.source, state)
}
state.write(';')
}
},
ExportAllDeclaration(node, state) {
if (node.exported != null) {
state.write('export * as ' + node.exported.name + ' from ')
} else {
state.write('export * from ')
}
this.Literal(node.source, state)
state.write(';')
},
MethodDefinition(node, state) {
if (node.static) {
state.write('static ')
}
const kind = node.kind[0]
if (kind === 'g' || kind === 's') {
// Getter or setter
state.write(node.kind + ' ')
}
if (node.value.async) {
state.write('async ')
}
if (node.value.generator) {
state.write('*')
}
if (node.computed) {
state.write('[')
this[node.key.type](node.key, state)
state.write(']')
} else {
this[node.key.type](node.key, state)
}
formatSequence(state, node.value.params)
state.write(' ')
this[node.value.body.type](node.value.body, state)
},
ClassExpression(node, state) {
this.ClassDeclaration(node, state)
},
ArrowFunctionExpression(node, state) {
state.write(node.async ? 'async ' : '', node)
const { params } = node
if (params != null) {
// Omit parenthesis if only one named parameter
if (params.length === 1 && params[0].type[0] === 'I') {
// If params[0].type[0] starts with 'I', it can't be `ImportDeclaration` nor `IfStatement` and thus is `Identifier`
state.write(params[0].name, params[0])
} else {
formatSequence(state, node.params)
}
}
state.write(' => ')
if (node.body.type[0] === 'O') {
// Body is an object expression
state.write('(')
this.ObjectExpression(node.body, state)
state.write(')')
} else {
this[node.body.type](node.body, state)
}
},
ThisExpression(node, state) {
state.write('this', node)
},
Super(node, state) {
state.write('super', node)
},
RestElement: (RestElement = function (node, state) {
state.write('...')
this[node.argument.type](node.argument, state)
}),
SpreadElement: RestElement,
YieldExpression(node, state) {
state.write(node.delegate ? 'yield*' : 'yield')
if (node.argument) {
state.write(' ')
this[node.argument.type](node.argument, state)
}
},
AwaitExpression(node, state) {
state.write('await ', node)
formatExpression(state, node.argument, node)
},
TemplateLiteral(node, state) {
const { quasis, expressions } = node
state.write('`')
const { length } = expressions
for (let i = 0; i < length; i++) {
const expression = expressions[i]
const quasi = quasis[i]
state.write(quasi.value.raw, quasi)
state.write('${')
this[expression.type](expression, state)
state.write('}')
}
const quasi = quasis[quasis.length - 1]
state.write(quasi.value.raw, quasi)
state.write('`')
},
TemplateElement(node, state) {
state.write(node.value.raw, node)
},
TaggedTemplateExpression(node, state) {
this[node.tag.type](node.tag, state)
this[node.quasi.type](node.quasi, state)
},
ArrayExpression: (ArrayExpression = function (node, state) {
state.write('[')
if (node.elements.length > 0) {
const { elements } = node,
{ length } = elements
for (let i = 0; ; ) {
const element = elements[i]
if (element != null) {
this[element.type](element, state)
}
if (++i < length) {
state.write(', ')
} else {
if (element == null) {
state.write(', ')
}
break
}
}
}
state.write(']')
}),
ArrayPattern: ArrayExpression,
ObjectExpression(node, state) {
const indent = state.indent.repeat(state.indentLevel++)
const { lineEnd, writeComments } = state
const propertyIndent = indent + state.indent
state.write('{')
if (node.properties.length > 0) {
state.write(lineEnd)
if (writeComments && node.comments != null) {
formatComments(state, node.comments, propertyIndent, lineEnd)
}
const comma = ',' + lineEnd
const { properties } = node,
{ length } = properties
for (let i = 0; ; ) {
const property = properties[i]
if (writeComments && property.comments != null) {
formatComments(state, property.comments, propertyIndent, lineEnd)
}
state.write(propertyIndent)
this[property.type](property, state)
if (++i < length) {
state.write(comma)
} else {
break
}
}
state.write(lineEnd)
if (writeComments && node.trailingComments != null) {
formatComments(state, node.trailingComments, propertyIndent, lineEnd)
}
state.write(indent + '}')
} else if (writeComments) {
if (node.comments != null) {
state.write(lineEnd)
formatComments(state, node.comments, propertyIndent, lineEnd)
if (node.trailingComments != null) {
formatComments(state, node.trailingComments, propertyIndent, lineEnd)
}
state.write(indent + '}')
} else if (node.trailingComments != null) {
state.write(lineEnd)
formatComments(state, node.trailingComments, propertyIndent, lineEnd)
state.write(indent + '}')
} else {
state.write('}')
}
} else {
state.write('}')
}
state.indentLevel--
},
Property(node, state) {
if (node.method || node.kind[0] !== 'i') {
// Either a method or of kind `set` or `get` (not `init`)
this.MethodDefinition(node, state)
} else {
if (!node.shorthand) {
if (node.computed) {
state.write('[')
this[node.key.type](node.key, state)
state.write(']')
} else {
this[node.key.type](node.key, state)
}
state.write(': ')
}
this[node.value.type](node.value, state)
}
},
ObjectPattern(node, state) {
state.write('{')
if (node.properties.length > 0) {
const { properties } = node,
{ length } = properties
for (let i = 0; ; ) {
this[properties[i].type](properties[i], state)
if (++i < length) {
state.write(', ')
} else {
break
}
}
}
state.write('}')
},
SequenceExpression(node, state) {
formatSequence(state, node.expressions)
},
UnaryExpression(node, state) {
if (node.prefix) {
const {
operator,
argument,
argument: { type },
} = node
state.write(operator)
const needsParentheses = expressionNeedsParenthesis(state, argument, node)
if (
!needsParentheses &&
(operator.length > 1 ||
(type[0] === 'U' &&
(type[1] === 'n' || type[1] === 'p') &&
argument.prefix &&
argument.operator[0] === operator &&
(operator === '+' || operator === '-')))
) {
// Large operator or argument is UnaryExpression or UpdateExpression node
state.write(' ')
}
if (needsParentheses) {
state.write(operator.length > 1 ? ' (' : '(')
this[type](argument, state)
state.write(')')
} else {
this[type](argument, state)
}
} else {
// FIXME: This case never occurs
this[node.argument.type](node.argument, state)
state.write(node.operator)
}
},
UpdateExpression(node, state) {
// Always applied to identifiers or members, no parenthesis check needed
if (node.prefix) {
state.write(node.operator)
this[node.argument.type](node.argument, state)
} else {
this[node.argument.type](node.argument, state)
state.write(node.operator)
}
},
AssignmentExpression(node, state) {
this[node.left.type](node.left, state)
state.write(' ' + node.operator + ' ')
this[node.right.type](node.right, state)
},
AssignmentPattern(node, state) {
this[node.left.type](node.left, state)
state.write(' = ')
this[node.right.type](node.right, state)
},
BinaryExpression: (BinaryExpression = function (node, state) {
const isIn = node.operator === 'in'
if (isIn) {
// Avoids confusion in `for` loops initializers
state.write('(')
}
formatExpression(state, node.left, node, false)
state.write(' ' + node.operator + ' ')
formatExpression(state, node.right, node, true)
if (isIn) {
state.write(')')
}
}),
LogicalExpression: BinaryExpression,
ConditionalExpression(node, state) {
const { test } = node
const precedence = state.expressionsPrecedence[test.type]
if (
precedence === NEEDS_PARENTHESES ||
precedence <= state.expressionsPrecedence.ConditionalExpression
) {
state.write('(')
this[test.type](test, state)
state.write(')')
} else {
this[test.type](test, state)
}
state.write(' ? ')
this[node.consequent.type](node.consequent, state)
state.write(' : ')
this[node.alternate.type](node.alternate, state)
},
NewExpression(node, state) {
state.write('new ')
const precedence = state.expressionsPrecedence[node.callee.type]
if (
precedence === NEEDS_PARENTHESES ||
precedence < state.expressionsPrecedence.CallExpression ||
hasCallExpression(node.callee)
) {
state.write('(')
this[node.callee.type](node.callee, state)
state.write(')')
} else {
this[node.callee.type](node.callee, state)
}
formatSequence(state, node['arguments'])
},
CallExpression(node, state) {
const precedence = state.expressionsPrecedence[node.callee.type]
if (
precedence === NEEDS_PARENTHESES ||
precedence < state.expressionsPrecedence.CallExpression
) {
state.write('(')
this[node.callee.type](node.callee, state)
state.write(')')
} else {
this[node.callee.type](node.callee, state)
}
if (node.optional) {
state.write('?.')
}
formatSequence(state, node['arguments'])
},
ChainExpression(node, state) {
this[node.expression.type](node.expression, state)
},
MemberExpression(node, state) {
const precedence = state.expressionsPrecedence[node.object.type]
if (
precedence === NEEDS_PARENTHESES ||
precedence < state.expressionsPrecedence.MemberExpression
) {
state.write('(')
this[node.object.type](node.object, state)
state.write(')')
} else {
this[node.object.type](node.object, state)
}
if (node.computed) {
if (node.optional) {
state.write('?.')
}
state.write('[')
this[node.property.type](node.property, state)
state.write(']')
} else {
if (node.optional) {
state.write('?.')
} else {
state.write('.')
}
this[node.property.type](node.property, state)
}
},
MetaProperty(node, state) {
state.write(node.meta.name + '.' + node.property.name, node)
},
Identifier(node, state) {
state.write(node.name, node)
},
Literal(node, state) {
if (node.raw != null) {
// Non-standard property
state.write(node.raw, node)
} else if (node.regex != null) {
this.RegExpLiteral(node, state)
} else if (node.bigint != null) {
state.write(node.bigint + 'n', node)
} else {
state.write(stringify(node.value), node)
}
},
RegExpLiteral(node, state) {
const { regex } = node
state.write(`/${regex.pattern}/${regex.flags}`, node)
},
}
const EMPTY_OBJECT = {}
/*
DEPRECATED: Alternate export of `GENERATOR`.
*/
export const baseGenerator = GENERATOR
class State {
constructor(options) {
const setup = options == null ? EMPTY_OBJECT : options
this.output = ''
// Functional options
if (setup.output != null) {
this.output = setup.output
this.write = this.writeToStream
} else {
this.output = ''
}
this.generator = setup.generator != null ? setup.generator : GENERATOR
this.expressionsPrecedence =
setup.expressionsPrecedence != null
? setup.expressionsPrecedence
: EXPRESSIONS_PRECEDENCE
// Formating setup
this.indent = setup.indent != null ? setup.indent : ' '
this.lineEnd = setup.lineEnd != null ? setup.lineEnd : '\n'
this.indentLevel =
setup.startingIndentLevel != null ? setup.startingIndentLevel : 0
this.writeComments = setup.comments ? setup.comments : false
// Source map
if (setup.sourceMap != null) {
this.write =
setup.output == null ? this.writeAndMap : this.writeToStreamAndMap
this.sourceMap = setup.sourceMap
this.line = 1
this.column = 0
this.lineEndSize = this.lineEnd.split('\n').length - 1
this.mapping = {
original: null,
// Uses the entire state to avoid generating ephemeral objects
generated: this,
name: undefined,
source: setup.sourceMap.file || setup.sourceMap._file,
}
}
}
write(code) {
this.output += code
}
writeToStream(code) {
this.output.write(code)
}
writeAndMap(code, node) {
this.output += code
this.map(code, node)
}
writeToStreamAndMap(code, node) {
this.output.write(code)
this.map(code, node)
}
map(code, node) {
if (node != null) {
const { type } = node
if (type[0] === 'L' && type[2] === 'n') {
// LineComment
this.column = 0
this.line++
return
}
if (node.loc != null) {
const { mapping } = this
mapping.original = node.loc.start
mapping.name = node.name
this.sourceMap.addMapping(mapping)
}
if (
(type[0] === 'T' && type[8] === 'E') ||
(type[0] === 'L' && type[1] === 'i' && typeof node.value === 'string')
) {
// TemplateElement or Literal string node
const { length } = code
let { column, line } = this
for (let i = 0; i < length; i++) {
if (code[i] === '\n') {
column = 0
line++
} else {
column++
}
}
this.column = column
this.line = line
return
}
}
const { length } = code
const { lineEnd } = this
if (length > 0) {
if (
this.lineEndSize > 0 &&
(lineEnd.length === 1
? code[length - 1] === lineEnd
: code.endsWith(lineEnd))
) {
this.line += this.lineEndSize
this.column = 0
} else {
this.column += length
}
}
}
toString() {
return this.output
}
}
export function generate(node, options) {
/*
Returns a string representing the rendered code of the provided AST `node`.
The `options` are:
- `indent`: string to use for indentation (defaults to `␣␣`)
- `lineEnd`: string to use for line endings (defaults to `\n`)
- `startingIndentLevel`: indent level to start from (defaults to `0`)
- `comments`: generate comments if `true` (defaults to `false`)
- `output`: output stream to write the rendered code to (defaults to `null`)
- `generator`: custom code generator (defaults to `GENERATOR`)
- `expressionsPrecedence`: custom map of node types and their precedence level (defaults to `EXPRESSIONS_PRECEDENCE`)
*/
const state = new State(options)
// Travel through the AST node and generate the code
state.generator[node.type](node, state)
return state.output
}