Source: polyfill/String.js

// Licensed Materials - Property of IBM
//
// IBM Watson Analytics
//
// (C) Copyright IBM Corp. 2015
//
// US Government Users Restricted Rights - Use, duplication or
// disclosure restricted by GSA ADP Schedule Contract with IBM Corp.

( function( Math, RegExp, String, ObjectPolyfill )
{
"use strict";
var strUndef = "undefined";

/**
 * Polyfills for {@link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String String}.
 * @class module:barejs/polyfill.String
 */

/** @lends module:barejs/polyfill.String */
var stat = {},
/** @lends module:barejs/polyfill.String# */
    proto = {};
/*jshint bitwise:false*/

function stringContext( _context, _name )
{
    if ( ( typeof _context === strUndef ) || ( _context === null ) )
        throw new TypeError( "String.prototype." + _name + " called on null or undefined" );

    return String( _context );
}

function toSearch( _search, _name )
{
    if ( _search instanceof RegExp )
        throw new TypeError( "First argument to String.prototype." + _name + " must not be a regular expression" );
    return String( _search );
}

function toNumber( _value, _min, _default, _max )
{
    if ( isNaN( _value = Math.trunc( _value ) ) )
        return _default;
    return _value < _min ? _min : ( _value > _max ? _max : _value );
}

/*istanbul ignore else: We test with __ES__ set to 3*/
if ( __ES__ < 6 )
{
    /**
     * Check if the string starts with the other string
     * @param {string} _search The part to search for
     * @param {number} [_start=0] Optional: The position in this string at which to begin searching for _search; defaults to 0.
     * @returns {boolean} True if the string starts with search, false otherwise.
     */
    proto.startsWith = function startsWith( _search/*, _start*/ )
    {
        var str = stringContext( this, "startsWith" ),
            pos = toNumber( arguments[1], 0, 0, str.length );
        // Using lastIndexOf ensures we don't search the whole string for _search, just at the requested pos index going back.
        return str.lastIndexOf( toSearch( _search, "startsWith" ), pos ) === pos;
    };

    /**
     * Check if the string ends with the other string
     * @param {string} _search The part to search for
     * @param {number} [_limit] Optional: Search within this string as if this string were only this long;
     * defaults to this string's actual length, clamped within the range established by this string's length.
     * @returns {boolean} True if the string ends with search, false otherwise.
     */
    proto.endsWith = function endsWith( _search/*, _limit*/ )
    {
        var str = stringContext( this, "endsWith" ),
            // We need to start matching at this position
            pos = toNumber( arguments[1], 0, str.length, str.length ) - ( _search = toSearch( _search, "endsWith" ) ).length;
        // Using indexOf ensures we don't search the whole string for _search, just at the requested end index going forward.
        return ( pos >= 0 ) && str.indexOf( _search, pos ) === pos;
    };

    ( function( _whitespace )
    {
        var reTrim = /^\s+|\s+$/g;
        var reTrimStart = /^\s+/;
        var reTrimEnd = /\s+$/;

        /*
         * Attempt to sniff out regular expression engines that do not have all whitespace under the \s character class.
         * If so, build the same regex as above, but with our expanded whitespace class.
         */
        /*istanbul ignore if: This check only fails in very old IE versions (<IE6)*/
        if ( _whitespace.match( /[^\s]/ ) )
        {
            reTrim = new RegExp( "^[\\s" + _whitespace + "]+|[\\s" + _whitespace + "]+$", "g" );
            reTrimStart = new RegExp( "^[\\s" + _whitespace + "]+" );
            reTrimEnd = new RegExp( "[\\s" + _whitespace + "]+$" );
        }

        /**
         * The trim() method removes whitespace from both ends of a string. Whitespace in this context is
         * all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator
         * characters (LF, CR, etc.).
         * @returns {string} The trimmed string.
         */
        proto.trim = function trim()
        {
            // jshint validthis:true
            return stringContext( this, "trim" ).replace( reTrim, "" );
        };

        /**
         * The trimStart() method removes whitespace from the beginning of a string. Whitespace in this context is
         * all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator
         * characters (LF, CR, etc.).
         * @returns {string} The trimmed string.
         */
        proto.trimStart = proto.trimLeft = function trimStart()
        {
            // jshint validthis:true
            return stringContext( this, "trimStart" ).replace( reTrimStart, "" );
        };

        /**
         * The trimEnd() method removes whitespace from the end of a string. Whitespace in this context is
         * all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator
         * characters (LF, CR, etc.).
         * @returns {string} The trimmed string.
         */
        proto.trimEnd = proto.trimRight = function trimEnd()
        {
            // jshint validthis:true
            return stringContext( this, "trimEnd" ).replace( reTrimEnd, "" );
        };
    }( String.fromCharCode(
        // \u00A0, NO-BREAK SPACE
        160,
        // \u1680, OGHAM SPACE MARK
        5760,
        // \u2000..\u200A, EN QUAD..HAIR SPACE
        8192, 8193, 8194, 8195, 8196, 8197, 8198, 8199, 8200, 8201, 8202,
        // \u2028, LINE SEPARATOR
        8232,
        // \u2029, PARAGRAPH SEPARATOR
        8233,
        // \u202F, NARROW NO-BREAK SPACE
        8239,
        // \u205F, MEDIUM MATHEMATICAL SPACE
        8287,
        // \u3000, IDEOGRAPHIC SPACE
        12288
    ) ) );

    ( function()
    {
        // Ensuring count is a 31-bit integer allows us to heavily optimise the main part of the method.
        // Besides that, browsers that will need this polyfill can't handle strings 1 << 28 chars or longer.
        var LIMIT = 1 << 28;

        /**
         * The repeat() method constructs and returns a new string which contains the specified number
         * of copies of the string on which it was called, concatenated together.
         * @param {number} _count The amount of times to repeat the number.
         * @returns {string} The string, repeated.
         */
        proto.repeat = function repeat( _count )
        {
            // jshint validthis:true
            var rpt = "",
                str = stringContext( this, "repeat" ),
                count = Math.floor( _count ) || 0;

            if ( count < 0 )
                throw new RangeError( "repeat count must be non-negative" );
            if ( count === Infinity )
                throw new RangeError( "repeat count must be less than infinity" );

            // If either string.length or count is 0, we'll get length 0
            var len = str.length * count;

            if ( len >= LIMIT )
                throw new RangeError( "repeat count must not overflow maximum string size" );

            if ( len > 0 )
            {
                // Optimised: concatenates str instead of rpt, to perform the operation with the least
                // amount of string concatenations possible.
                for (;;)
                {
                    if ( ( count & 1 ) === 1 )
                        rpt += str;
                    count >>>= 1;
                    if ( count === 0 )
                        break;
                    str += str;
                }
            }

            return rpt;
        };
    }() );

    /**
     * The codePointAt() method returns a non-negative integer that is the UTF-16 encoded code point value.
     * @param {number} _position The index at which the code point should be read
     * @returns {number} The code point value, or undefined if _position is out of range.
     */
    proto.codePointAt = function codePointAt( _position )
    {
        var str = stringContext( this, "codePointAt" ),
            len = str.length,
            // `ToInteger`
            i = Math.floor( _position ) || 0,
            result;

        // Account for out-of-bounds indices:
        if ( i >= 0 && i < len )
        {
            // Get the first code unit; increment index afterwards
            result = str.charCodeAt( i++ );
            // check if it’s the start of a surrogate pair
            // high surrogate && there is a next code unit
            if ( ( result >= 0xD800 ) && ( result <= 0xDBFF ) && ( i < len ) )
            {
                var pair = str.charCodeAt( i );
                if ( ( pair >= 0xDC00 ) && ( pair <= 0xDFFF ) ) // low surrogate
                    result = ( result - 0xD800 ) * 0x400 + pair - 0xDC00 + 0x10000;
            }
        }

        return result;
    };

    /**
     * Create a String from any number of codepoint values
     * @returns {string} The created string
     */
    stat.fromCodePoint = function fromCodePoint( _firstCodePoint )
    {
        var codeUnits = [],
            result = "";

        for ( var i = 0, len = arguments.length; i < len; ++i )
        {
            var codePoint = +( arguments[i] );
            if (
                    ( !isFinite( codePoint ) ) ||                       // `NaN`, `+Infinity`, or `-Infinity`
                    ( codePoint < 0 ) || ( codePoint > 0x10FFFF ) ||    // not a valid Unicode code point
                    ( Math.floor( codePoint ) !== codePoint )           // not an integer
                )
            {
                throw new RangeError( "Invalid code point: " + codePoint );
            }
            if ( codePoint <= 0xFFFF )
            {
                // BMP code point
                codeUnits.push( codePoint );
            }
            else
            {
                // Astral code point; split in surrogate halves
                codePoint -= 0x10000;
                var highSurrogate = ( codePoint >> 10 ) + 0xD800;
                var lowSurrogate = ( codePoint % 0x400 ) + 0xDC00;
                codeUnits.push( highSurrogate, lowSurrogate );
            }
            if ( ( i + 1 === len ) || ( codeUnits.length > 0x4000 ) )
            {
                result += String.fromCharCode.apply( String, codeUnits );
                codeUnits.length = 0;
            }
        }
        return result;
    };

    /**
     * Check if the string includes the other string
     * @param {string} _search The part to search for
     * @param {number} [_position=0] Optional: The index to start searching at. Defaults to 0.
     * @returns {boolean} True if the string includes search, false otherwise.
     */
    proto.includes = function includes( _search/*, _position*/ )
    {
        var str = stringContext( this, "includes" ),
            pos = toNumber( arguments[1], 0, 0, str.length );
        return str.indexOf( toSearch( _search, "includes" ), pos ) >= 0;
    };

// End of ES6 polyfill scope
}

/*istanbul ignore else: We test with __ES__ set to 3*/
if ( __ES__ < 7 )
{
    /**
     * The padStart() method pads the current string with a given string (eventually repeated) so that the resulting string reaches a given length.
     * The pad is applied from the start (left) of the current string.
     * @param {number} _targetLength The length of the resulting string once the current string has been padded.
     *      If this parameter is smaller than the current string's length, the current string will be returned as it is.
     * @param {string} [_padString=" "] The string to pad the current string with.
     *      If this string is too long, it will be truncated and the left-most part will be applied.
     *      The default value for this parameter is " " (U+0020).
     */
    proto.padStart = function padStart( _targetLength/*, _padString*/ )
    {
        var str = stringContext( this, "padStart" ),
            pad = arguments[1],
            len = Math.trunc( _targetLength ) || 0,
            add = len - str.length,
            pLen,
            pre;

        pad = typeof pad === strUndef ? " " : String( pad );
        pLen = pad.length;

        if ( ( add > 0 ) && ( pLen > 0 ) )
        {
            pre = pad.repeat( Math.floor( add / pLen ) );
            add %= pLen;
            if ( add > 0 )
                pre += pad.substr( 0, add );
            str = pre + str;
        }
        return str;
    };

    /**
     * The padEnd() method pads the current string with a given string (eventually repeated) so that the resulting string reaches a given length.
     * The pad is applied from the end (right) of the current string.
     * @param {number} _targetLength The length of the resulting string once the current string has been padded.
     *      If this parameter is smaller than the current string's length, the current string will be returned as it is.
     * @param {string} [_padString=" "] The string to pad the current string with.
     *      If this string is too long, it will be truncated and the left-most part will be applied.
     *      The default value for this parameter is " " (U+0020).
     */
    proto.padEnd = function padEnd( _targetLength/*, _padString*/ )
    {
        var str = stringContext( this, "padEnd" ),
            pad = arguments[1],
            len = Math.trunc( _targetLength ) || 0,
            add = len - str.length,
            pLen,
            post;

        pad = typeof pad === strUndef ? " " : String( pad );
        pLen = pad.length;

        if ( ( add > 0 ) && ( pLen > 0 ) )
        {
            post = pad.repeat( Math.floor( add / pLen ) );
            add %= pLen;
            if ( add > 0 )
                post += pad.substr( 0, add );
            str += post;
        }
        return str;
    };
}

ObjectPolyfill.polyfill( String, stat, proto, exports, "String" );

// End of module
}( Math, RegExp, String, require( "./Object" ) ) );