# tr46.js > An implementation of the [Unicode TR46 specification](http://unicode.org/reports/tr46/). ## Installation [Node.js](http://nodejs.org) `>= 6` is required. To install, type this at the command line: ```shell npm install tr46 ``` ## API ### `toASCII(domainName[, options])` Converts a string of Unicode symbols to a case-folded Punycode string of ASCII symbols. Available options: * [`checkBidi`](#checkBidi) * [`checkHyphens`](#checkHyphens) * [`checkJoiners`](#checkJoiners) * [`processingOption`](#processingOption) * [`useSTD3ASCIIRules`](#useSTD3ASCIIRules) * [`verifyDNSLength`](#verifyDNSLength) ### `toUnicode(domainName[, options])` Converts a case-folded Punycode string of ASCII symbols to a string of Unicode symbols. Available options: * [`checkBidi`](#checkBidi) * [`checkHyphens`](#checkHyphens) * [`checkJoiners`](#checkJoiners) * [`useSTD3ASCIIRules`](#useSTD3ASCIIRules) ## Options ### `checkBidi` Type: `Boolean` Default value: `false` When set to `true`, any bi-directional text within the input will be checked for validation. ### `checkHyphens` Type: `Boolean` Default value: `false` When set to `true`, the positions of any hyphen characters within the input will be checked for validation. ### `checkJoiners` Type: `Boolean` Default value: `false` When set to `true`, any word joiner characters within the input will be checked for validation. ### `processingOption` Type: `String` Default value: `"nontransitional"` When set to `"transitional"`, symbols within the input will be validated according to the older IDNA2003 protocol. When set to `"nontransitional"`, the current IDNA2008 protocol will be used. ### `useSTD3ASCIIRules` Type: `Boolean` Default value: `false` When set to `true`, input will be validated according to [STD3 Rules](http://unicode.org/reports/tr46/#STD3_Rules). ### `verifyDNSLength` Type: `Boolean` Default value: `false` When set to `true`, the length of each DNS label within the input will be checked for validation.