Literal Toolkit

A toolkit to parse and generate JavaScript style literals.

In case to write a pseudo code implementation or data structure, this toolkit will help a lot on parsing and generating strings, numbers, regular expressions, keyword values, and even comments.

Install

$ npm i literal-toolkit

API

There are several interfaces under this package, each of them have the similar functions that can be used to parse and generate literals.

• LiteralToken

  • source: string will exclude any leading spaces.
  • offset: number the index position where source starts.
  • length: number the length of the source string.

• string

  • StringToken extends LiteralToken
    • value: string
    • quote: "'" | """ | "`"
  • parse(str: string): string
  • parseToken(str: string): StringToken
  • toLiteral(str: string, quote?: "'" | """ | "`"): string

• number

  • NumberToken extends LiteralToken
    • value: number | bigint
    • radix: 2 | 8 | 10 | 16
  • parse(str: string, strict?: boolean): number | bigint
  • parseToken(str: string): NumberToken
  • isBin(str: string): boolean
  • isOct(str: string): boolean
  • isDec(str: string): boolean
  • isHex(str: string): boolean
  • isNaN(str: string): boolean
  • isFinite(str: string): boolean
  • isBigInt(str: string): boolean
  • toLiteral(num: number | bigint, radix?: 2 | 8 | 10 | 16): string

• keyword Includes true, false, null, NaN and Infinity

  • KeywordToken extends LiteralToken
    • value: true | false | null | number
  • parse(str: string): KeywordToken["value"]
  • parseToken(str: string): KeywordToken
  • toLiteral(keyword: KeywordToken["value"]): string

• regexp

  • RegExpToken extends LiteralToken
    • value: RegExp
  • parse(str: string): RegExp
  • parseToken(str: string): RegExpToken
  • toLiteral(re: RegExp): string

• comment

  • CommentToken extends LiteralToken
    • value: string
    • type: "//" | "/*" | "/**"
  • parse(str: string, strip?: boolean): string
  • parseToken(str: string): CommentToken
  • toLiteral(str: string, type?: "//" | "/*" | "/**", inden?: string): string

All parseToken() functions, when the given string cannot be parsed, will return null by default.

All parse() functions are short-cuts of parseToken(str).value (might include additional features). All these functions, when the given string cannot be parsed, will return undefined instead.

All parse() functions are just for simple parsing usage, when dealing with complex scenarios, use parseToken() instead.

For detailed API documentation, please redirect to interface declarations.

Usage

import { string, number, keyword, regexp, comment } from "literal-toolkit";

string.parse('"this is a double-quoted string literal"');
string.parse("'this is a single-quoted string literal'");
string.parse("`this is a back-quoted\n and multi-line string`");

number.parse("1234567"); // decimal number: 1234567
number.parse("0b1010101"); // binary number: 0b1010101
number.parse("0o1234567"); // octal number: 0o1234567
number.parse("01234567"); // octal number without 'o': 01234567
number.parse("0x1234567"); // hexadecimal number: 0x1234567

keyword.parse("true"); // boolean: true
keyword.parse("false"); // boolean: false
keyword.parse("null"); // null
keyword.parse("NaN"); // number: NaN
keyword.parse("Infinity"); // number: Infinity

regexp.parse("/[a-zA-Z0-9]/i"); // RegExp: /[a-zA-Z0-9]/i

comment.parse("// this is a single-line comment");
comment.parse("/* this is a inline comment */");
comment.parse("/* this comment contains\n multiple\n lines */");
comment.parse("/** this is a JSDoc comment */");

This toolkit is meant to parse any valid JavaScript literal strings (of supported types) into real values, so any form that works in JavaScript syntax can be parsed by this package, although the above example doesn't cover that much. Check the test for more examples.