Chunk String (v3)

Revision 3 of this benchmark created by Xotic750 on August 28, 2015

Description

Preparation HTML

<script>
var chunkSizes = [],
    maxChunkSize = 512,
    testString = '',
    maxTestString = 100000,
    chunkSize = 0,
    index;

for (index = 1; chunkSize < maxChunkSize; index += 1) {
    chunkSize = Math.pow(2, index);
    chunkSizes.push(chunkSize);
}

for (index = 0; index < maxTestString; index += 1) {
    testString += String.fromCharCode(Math.floor(Math.random() * 95) + 32);
}

function test(fn) {
    for (var czIndex = 0; czIndex < chunkSizes.length; czIndex += 1) {
        fn(testString, chunkSizes[czIndex]);
    }
}

function chunkSubstr1(str, size) {
  var chunks = new Array(str.length / size + .5 | 0),
      nChunks = chunks.length;

  var newo = 0;
  for(var i = 0, o = 0; i < nChunks; ++i, o = newo) {
    newo += size;
    chunks[i] = str.substr(o, size);
  }

  return chunks;
}

function chunkSubstr2(str, size) {
  var numChunks = str.length / size + .5 | 0,
      chunks = new Array(numChunks);

  for(var i = 0, o = 0; i < numChunks; ++i, o += size) {
    chunks[i] = str.substr(o, size);
  }

  return chunks;
}

function chunkRegex(str, size) {
  var re = new RegExp('(.|[\\r\\n]){1,' + size + '}', 'g');
  return str.match(re);
}

function chunkString1(str, len) {
  var _size = Math.ceil(str.length/len),
      _ret  = new Array(_size),
      _offset
  ;

  for(var _i=0; _i<_size; _i++) {
    _offset = _i * len;
    _ret[_i] = str.substring(_offset, _offset + len);
  }

  return _ret;
}

function chunkString2(str, len) {
  var size = str.length / len + .5 | 0,
      ret  = new Array(size),
      offset = 0;

  for(var i = 0; i < size; ++i, offset += len) {
    ret[i] = str.substring(offset, offset + len);
  }

  return ret;
}

/*jslint maxlen:80, browser:true, devel:true */

/*
 * Properties used by toChunks.
 */

/*property
    MAX_SAFE_INTEGER, abs, ceil, configurable, defineProperty, enumerable,
    floor, length, max, min, pow, prototype, protoype, slice, toChunks, value,
    writable
*/

/*
 * Properties used in the testing of toChunks implimentation.
 */

/*property
    appendChild, createTextNode, floor, fromCharCode, getElementById, length,
    log, pow, push, random, toChunks
*/

(function () {
    'use strict';

    var MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER || Math.pow(2, 53) - 1;

    /**
     * Defines a new property directly on an object, or modifies an existing
     * property on an object, and returns the object.
     *
     * @private
     * @function
     * @param {Object} object
     * @param {string} property
     * @param {Object} descriptor
     * @return {Object}
     * @see https://goo.gl/CZnEqg
     */
    function $defineProperty(object, property, descriptor) {
        if (Object.defineProperty) {
            Object.defineProperty(object, property, descriptor);
        } else {
            object[property] = descriptor.value;
        }

        return object;
    }

    /**
     * Returns true if the operands are strictly equal with no type conversion.
     *
     * @private
     * @function
     * @param {*} a
     * @param {*} b
     * @return {boolean}
     * @see http://www.ecma-international.org/ecma-262/5.1/#sec-11.9.4
     */
    function $strictEqual(a, b) {
        return a === b;
    }

    /**
     * Returns true if the operand inputArg is undefined.
     *
     * @private
     * @function
     * @param {*} inputArg
     * @return {boolean}
     */
    function $isUndefined(inputArg) {
        return $strictEqual(typeof inputArg, 'undefined');
    }

    /**
     * The abstract operation throws an error if its argument is a value that
     * cannot be converted to an Object, otherwise returns the argument.
     *
     * @private
     * @function
     * @param {*} inputArg The object to be tested.
     * @throws {TypeError} If inputArg is null or undefined.
     * @return {*} The inputArg if coercible.
     * @see https://goo.gl/5GcmVq
     */
    function $requireObjectCoercible(inputArg) {
        var errStr;

        if (inputArg === null || $isUndefined(inputArg)) {
            errStr = 'Cannot convert argument to object: ' + inputArg;
            throw new TypeError(errStr);
        }

        return inputArg;
    }

    /**
     * The abstract operation converts its argument to a value of type string
     *
     * @private
     * @function
     * @param {*} inputArg
     * @return {string}
     * @see https://people.mozilla.org/~jorendorff/es6-draft.html#sec-tostring
     */
    function $toString(inputArg) {
        var type,
            val;

        if (inputArg === null) {
            val = 'null';
        } else {
            type = typeof inputArg;
            if (type === 'string') {
                val = inputArg;
            } else if (type === 'undefined') {
                val = type;
            } else {
                if (type === 'symbol') {
                    throw new TypeError('Cannot convert symbol to string');
                }

                val = String(inputArg);
            }
        }

        return val;
    }

    /**
     * Returns a string only if the arguments is coercible otherwise throws an
     * error.
     *
     * @private
     * @function
     * @param {*} inputArg
     * @throws {TypeError} If inputArg is null or undefined.
     * @return {string}
     */
    function $onlyCoercibleToString(inputArg) {
        return $toString($requireObjectCoercible(inputArg));
    }

    /**
     * The function evaluates the passed value and converts it to an integer.
     *
     * @private
     * @function
     * @param {*} inputArg The object to be converted to an integer.
     * @return {number} If the target value is NaN, null or undefined, 0 is
     *                   returned. If the target value is false, 0 is returned
     *                   and if true, 1 is returned.
     * @see http://www.ecma-international.org/ecma-262/5.1/#sec-9.4
     */
    function $toInteger(inputArg) {
        var number = +inputArg,
            val = 0;

        if ($strictEqual(number, number)) {
            if (!number || number === Infinity || number === -Infinity) {
                val = number;
            } else {
                val = (number > 0 || -1) * Math.floor(Math.abs(number));
            }
        }

        return val;
    }

    /**
     * The abstract operation ToLength converts its argument to an integer
     * suitable for use as the length of an array-like object.
     *
     * @private
     * @function
     * @param {*} inputArg The object to be converted to a length.
     * @return {number} If len <= +0 then +0 else if len is +INFINITY then
     *                   2^53-1 else min(len, 2^53-1).
     * @see https://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength
     */
    function $toLength(inputArg) {
        return Math.min(Math.max($toInteger(inputArg), 0), MAX_SAFE_INTEGER);
    }

    if (!String.prototype.toChunks) {
        /**
         * This method chunks a string into an array of strings of a specified
         * chunk size.
         *
         * @function
         * @this {string} The string to be chunked.
         * @param {Number} chunkSize The size of the chunks that the string will
         *                           be chunked into.
         * @returns {Array} Returns an array of the chunked string.
         */
        $defineProperty(String.prototype, 'toChunks', {
            enumerable: false,
            configurable: true,
            writable: true,
            value: function (chunkSize) {
                var str = $onlyCoercibleToString(this),
                    length = $toLength(str.length),
                    chunkLength = $toInteger(chunkSize),
                    numChunks = Math.ceil(length / chunkLength),
                    chunked = [],
                    index = 0,
                    start = 0,
                    end = chunkLength;

                chunked.length = numChunks;
                while (index < numChunks) {
                    chunked[index] = str.slice(start, end);
                    start = end;
                    end += chunkLength;
                    index += 1;
                }

                return chunked;
            }
        });
    }
}());

function chunkString3(str, len) {
    return str.toChunks(len);
}
</script>

Test runner

test(chunkSubstr1);

test(chunkSubstr2);

test(chunkRegex);

test(chunkString1);

test(chunkString2);

test(chunkString3);

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.

• Revision 1: published by Justin Warkentin on March 22, 2015
• Revision 3: published by Xotic750 on August 28, 2015