以原型函数的形式:

String.prototype.lsplit = function(){
    return this.match(new RegExp('.{1,'+ ((arguments.length==1)?(isFinite(String(arguments[0]).trim())?arguments[0]:false):1) +'}', 'g'));
}

比较match, slice, substr和substring 不同块大小的匹配和切片的比较 小块大小的匹配和切片的比较

底线:

match非常低效，slice更好，在Firefox上substr/substring更好 匹配对于短字符串来说效率更低(即使使用缓存的regex -可能是因为regex解析设置时间) 对于大块大小的匹配效率更低(可能是由于无法“跳跃”) 对于更长的字符串和非常小的块大小，match在旧的IE上优于slice，但在所有其他系统上仍然失败 jsperf岩石

这是我使用的代码，它使用string。prototype。slice。

是的，这是一个相当长的答案，因为它试图遵循当前的标准尽可能接近，当然包含了合理数量的JSDOC评论。然而，一旦缩小，代码只有828字节，一旦gzip传输，它只有497字节。

这个添加到String中的1方法。prototype(使用Object.defineProperty如果可用)是:

toChunks

包含了许多测试来检查功能。

担心代码的长度会影响性能?不用担心，http://jsperf.com/chunk-string/3

许多额外的代码是为了确保代码在多个javascript环境中响应相同。

/*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, 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), chunkLength = $toInteger(chunkSize), chunked = [], numChunks, length, index, start, end; if (chunkLength < 1) { return chunked; } length = $toLength(str.length); numChunks = Math.ceil(length / chunkLength); 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; } }); } }()); /* * Some tests */ (function () { 'use strict'; var pre = document.getElementById('out'), chunkSizes = [], maxChunkSize = 512, testString = '', maxTestString = 100000, chunkSize = 0, index = 1; while (chunkSize < maxChunkSize) { chunkSize = Math.pow(2, index); chunkSizes.push(chunkSize); index += 1; } index = 0; while (index < maxTestString) { testString += String.fromCharCode(Math.floor(Math.random() * 95) + 32); index += 1; } function log(result) { pre.appendChild(document.createTextNode(result + '\n')); } function test() { var strLength = testString.length, czLength = chunkSizes.length, czIndex = 0, czValue, result, numChunks, pass; while (czIndex < czLength) { czValue = chunkSizes[czIndex]; numChunks = Math.ceil(strLength / czValue); result = testString.toChunks(czValue); czIndex += 1; log('chunksize: ' + czValue); log(' Number of chunks:'); log(' Calculated: ' + numChunks); log(' Actual:' + result.length); pass = result.length === numChunks; log(' First chunk size: ' + result[0].length); pass = pass && result[0].length === czValue; log(' Passed: ' + pass); log(''); } } test(); log(''); log('Simple test result'); log('abcdefghijklmnopqrstuvwxyz'.toChunks(3)); }()); <pre id="out"></pre>

我会用正则表达式…

var chunkStr = function(str, chunkLength) {
    return str.match(new RegExp('[\\s\\S]{1,' + +chunkLength + '}', 'g'));
}

这是一个快速而直接的解决方案

function chunkString (str, len) { const size = Math.ceil(str.length/len) const r = Array(size) let offset = 0 for (let i = 0; i < size; i++) { r[i] = str.substr(offset, len) offset += len } return r } console.log(chunkString("helloworld", 3)) // => [ "hel", "low", "orl", "d" ] // 10,000 char string const bigString = "helloworld".repeat(1000) console.time("perf") const result = chunkString(bigString, 3) console.timeEnd("perf") console.log(result) // => perf: 0.385 ms // => [ "hel", "low", "orl", "dhe", "llo", "wor", ... ]

你可以在没有正则表达式的情况下使用reduce():

(str, n) => {
  return str.split('').reduce(
    (acc, rec, index) => {
      return ((index % n) || !(index)) ? acc.concat(rec) : acc.concat(',', rec)
    },
    ''
  ).split(',')
}