moodle/lib/yuilib/3.17.2/json-stringify-shim/json-stringify-shim.js

/*
YUI 3.17.2 (build 9c3c78e)
Copyright 2014 Yahoo! Inc. All rights reserved.
Licensed under the BSD License.
http://yuilibrary.com/license/
*/

YUI.add('json-stringify-shim', function (Y, NAME) {

// All internals kept private for security reasons
var Lang      = Y.Lang,
    isFunction= Lang.isFunction,
    isObject  = Lang.isObject,
    isArray   = Lang.isArray,
    _toStr    = Object.prototype.toString,
    UNDEFINED = 'undefined',
    OBJECT    = 'object',
    NULL      = 'null',
    STRING    = 'string',
    NUMBER    = 'number',
    BOOLEAN   = 'boolean',
    DATE      = 'date',
    _allowable= {
        'undefined'        : UNDEFINED,
        'string'           : STRING,
        '[object String]'  : STRING,
        'number'           : NUMBER,
        '[object Number]'  : NUMBER,
        'boolean'          : BOOLEAN,
        '[object Boolean]' : BOOLEAN,
        '[object Date]'    : DATE,
        '[object RegExp]'  : OBJECT
    },
    EMPTY     = '',
    OPEN_O    = '{',
    CLOSE_O   = '}',
    OPEN_A    = '[',
    CLOSE_A   = ']',
    COMMA     = ',',
    COMMA_CR  = ",\n",
    CR        = "\n",
    COLON     = ':',
    COLON_SP  = ': ',
    QUOTE     = '"',

    // Regex used to capture characters that need escaping before enclosing
    // their containing string in quotes.
    _SPECIAL = /[\x00-\x07\x0b\x0e-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,

    // Character substitution map for common escapes and special characters.
    _COMMON = [
        [/\\/g, '\\\\'],
        [/\"/g, '\\"'],
        [/\x08/g, '\\b'],
        [/\x09/g, '\\t'],
        [/\x0a/g, '\\n'],
        [/\x0c/g, '\\f'],
        [/\x0d/g, '\\r']
    ],
    _COMMON_LENGTH = _COMMON.length,

    // In-process optimization for special character escapes that haven't yet
    // been promoted to _COMMON
    _CHAR = {},

    // Per-char counter to determine if it's worth fast tracking a special
    // character escape sequence.
    _CHAR_COUNT, _CACHE_THRESHOLD;

// Utility function used to determine how to serialize a variable.
function _type(o) {
    var t = typeof o;
    return  _allowable[t] ||              // number, string, boolean, undefined
            _allowable[_toStr.call(o)] || // Number, String, Boolean, Date
            (t === OBJECT ?
                (o ? OBJECT : NULL) :     // object, array, null, misc natives
                UNDEFINED);               // function, unknown
}

// Escapes a special character to a safe Unicode representation
function _char(c) {
    if (!_CHAR[c]) {
        _CHAR[c] = '\\u'+('0000'+(+(c.charCodeAt(0))).toString(16)).slice(-4);
        _CHAR_COUNT[c] = 0;
    }

    // === to avoid this conditional for the remainder of the current operation
    if (++_CHAR_COUNT[c] === _CACHE_THRESHOLD) {
        _COMMON.push([new RegExp(c, 'g'), _CHAR[c]]);
        _COMMON_LENGTH = _COMMON.length;
    }

    return _CHAR[c];
}

// Enclose escaped strings in quotes
function _string(s) {
    var i, chr;

    // Preprocess the string against common characters to avoid function
    // overhead associated with replacement via function.
    for (i = 0; i < _COMMON_LENGTH; i++) {
        chr = _COMMON[i];
        s = s.replace(chr[0], chr[1]);
    }

    // original function replace for the not-as-common set of chars
    return QUOTE + s.replace(_SPECIAL, _char) + QUOTE;
}

// Adds the provided space to the beginning of every line in the input string
function _indent(s,space) {
    return s.replace(/^/gm, space);
}

Y.JSON.stringify = function _stringify(o,w,space) {
    if (o === undefined) {
        return undefined;
    }

    var replacer = isFunction(w) ? w : null,
        format   = _toStr.call(space).match(/String|Number/) || [],
        _date    = Y.JSON.dateToString,
        stack    = [],
        tmp,i,len;

    _CHAR_COUNT      = {};
    _CACHE_THRESHOLD = Y.JSON.charCacheThreshold;

    if (replacer || !isArray(w)) {
        w = undefined;
    }

    // Ensure whitelist keys are unique (bug 2110391)
    if (w) {
        tmp = {};
        for (i = 0, len = w.length; i < len; ++i) {
            tmp[w[i]] = true;
        }
        w = tmp;
    }

    // Per the spec, strings are truncated to 10 characters and numbers
    // are converted to that number of spaces (max 10)
    space = format[0] === 'Number' ?
                new Array(Math.min(Math.max(0,space),10)+1).join(" ") :
                (space || EMPTY).slice(0,10);

    function _serialize(h,key) {
        var value = h[key],
            t     = _type(value),
            a     = [],
            colon = space ? COLON_SP : COLON,
            arr, i, keys, k, v;

        // Per the ECMA 5 spec, toJSON is applied before the replacer is
        // called.  Also per the spec, Date.prototype.toJSON has been added, so
        // Date instances should be serialized prior to exposure to the
        // replacer.  I disagree with this decision, but the spec is the spec.
        if (isObject(value) && isFunction(value.toJSON)) {
            value = value.toJSON(key);
        } else if (t === DATE) {
            value = _date(value);
        }

        if (isFunction(replacer)) {
            value = replacer.call(h,key,value);
        }

        if (value !== h[key]) {
            t = _type(value);
        }

        switch (t) {
            case DATE    : // intentional fallthrough.  Pre-replacer Dates are
                           // serialized in the toJSON stage.  Dates here would
                           // have been produced by the replacer.
            case OBJECT  : break;
            case STRING  : return _string(value);
            case NUMBER  : return isFinite(value) ? value+EMPTY : NULL;
            case BOOLEAN : return value+EMPTY;
            case NULL    : return NULL;
            default      : return undefined;
        }

        // Check for cyclical references in nested objects
        for (i = stack.length - 1; i >= 0; --i) {
            if (stack[i] === value) {
                throw new Error("JSON.stringify. Cyclical reference");
            }
        }

        arr = isArray(value);

        // Add the object to the processing stack
        stack.push(value);

        if (arr) { // Array
            for (i = value.length - 1; i >= 0; --i) {
                a[i] = _serialize(value, i) || NULL;
            }
        } else {   // Object
            // If whitelist provided, take only those keys
            keys = w || value;
            i = 0;

            for (k in keys) {
                if (keys.hasOwnProperty(k)) {
                    v = _serialize(value, k);
                    if (v) {
                        a[i++] = _string(k) + colon + v;
                    }
                }
            }
        }

        // remove the array from the stack
        stack.pop();

        if (space && a.length) {
            return arr ?
                OPEN_A + CR + _indent(a.join(COMMA_CR), space) + CR + CLOSE_A :
                OPEN_O + CR + _indent(a.join(COMMA_CR), space) + CR + CLOSE_O;
        } else {
            return arr ?
                OPEN_A + a.join(COMMA) + CLOSE_A :
                OPEN_O + a.join(COMMA) + CLOSE_O;
        }
    }

    // process the input
    return _serialize({'':o},'');
};

// Property available for testing if the implementation being used
// is native or a shim
Y.JSON.stringify.isShim = true;


}, '3.17.2', {"requires": ["json-stringify"]});