Array.fill & String.padStart & String.padEnd

Array.fill & String.padStart & String.padEnd

Array.fill

arr.fill(value[, start[, end]])

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill

String.padStart & String.padEnd

str.padStart(targetLength [, padString])

str.padEnd(targetLength [, padString])

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padEnd

demos

const str1 = '13579';

const str2 = '13579';

console.log(str1.padStart(7));
// "  13579"

console.log(str2.padStart(7, ``));
// "13579"

const str1 = 'abc';
const str2 = 'abc';

console.log(str1.padEnd(7));
// "abc    "

console.log(str2.padEnd(7, ``));
// "abc"

js no for 100 array

"use strict";

/**
 *
 * @author xgqfrms
 * @license MIT
 * @copyright xgqfrms
 * @created 2020-07-20
 * @modified
 *
 * @description Array.fill
 * @difficulty Easy Medium Hard
 * @complexity O(n)
 * @augments
 * @example
 * @link https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/fill
 * @solutions
 *
 */

const log = console.log;

// arr.fill(value[, start[, end]])

const noForArrayAutoGenerator = (len = 100) => {
  return [...``.padStart(len, ` `)].map((item, i) => i + 1 + ``);
  // return [...``.padStart(len, ` `)].map((item, i) => i + 1);
  // return [...``.padStart(len, ` `)].map((item, i) => i + 1).map((item, i) => i % 2 === 0 ? item : item + ``);
}

const arr = noForArrayAutoGenerator(10);

log(`arr`, arr)
// 

arr.fill(``, 3, 7)

log(`new arr`, arr)
// 

refs

https://www.cnblogs.com/xgqfrms/p/8982974.html

https://www.zhihu.com/question/25218632/answer/1354060098

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