"use strict";

function hex( ch ) {

    return ch.charCodeAt( 0 ).toString( 16 ).toUpperCase();

}

function sourceEscape( s ) {

    return s
        .replace( /\0/g, "\\0" )    // null
        .replace( /\x08/g, "\\b" )  // backspace
        .replace( /\t/g, "\\t" )    // horizontal tab
        .replace( /\n/g, "\\n" )    // line feed
        .replace( /\v/g, "\\v" )    // vertical tab
        .replace( /\f/g, "\\f" )    // form feed
        .replace( /\r/g, "\\r" )    // carriage return
        .replace( /[\x00-\x0F]/g, ch => "\\x0" + hex( ch ) )
        .replace( /[\x10-\x1F\x7F-\xFF]/g, ch => "\\x" + hex( ch ) )
        .replace( /[\u0100-\u0FFF]/g, ch => "\\u0" + hex( ch ) )
        .replace( /[\u1000-\uFFFF]/g, ch => "\\u" + hex( ch ) );

}

// JavaScript code generation helpers.
const js = {

    /**
     * ECMA-262, 5th ed., 7.8.4: All characters may appear literally in a string
     * literal except for the closing quote character, backslash, carriage
     * return, line separator, paragraph separator, and line feed. Any character
     * may appear in the form of an escape sequence.
     *
     * For portability, we also escape all control and non-ASCII characters.
     */
    stringEscape( s ) {

        return sourceEscape( s
            .replace( /\\/g, "\\\\" )   // backslash
            .replace( /"/g, "\\\"" )    // closing double quote
        );

    },

    /**
     * Based on ECMA-262, 5th ed., 7.8.5 & 15.10.1.
     *
     * For portability, we also escape all control and non-ASCII characters.
     */
    regexpEscape( s ) {

        return sourceEscape( s
            .replace( /\\/g, "\\\\" )   // backslash
            .replace( /\//g, "\\/" )    // closing slash
            .replace( /]/g, "\\]" )     // closing bracket
            .replace( /\^/g, "\\^" )    // caret
            .replace( /-/g, "\\-" )     // dash
        );

    },

    /**
     * This is a list of reserved words for ECMA-262, 5th ed., 7.6.1 (strict mode)
     */
    reservedWords: [

        // Keyword
        "break",
        "case",
        "catch",
        "continue",
        "debugger",
        "default",
        "delete",
        "do",
        "else",
        "finally",
        "for",
        "function",
        "if",
        "in",
        "instanceof",
        "new",
        "return",
        "switch",
        "this",
        "throw",
        "try",
        "typeof",
        "var",
        "void",
        "while",
        "with",

        // FutureReservedWord
        "class",
        "const",
        "enum",
        "export",
        "extends",
        "implements",
        "import",
        "interface",
        "let",
        "package",
        "private",
        "protected",
        "public",
        "static",
        "super",
        "yield",

        // Literal
        "false",
        "null",
        "true",

    ],

};

module.exports = js;