phpjs/functions/array/array_pad.js

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function array_pad(input, pad_size, pad_value) {
  //  discuss at: http://phpjs.org/functions/array_pad/
  // original by: Waldo Malqui Silva
  //   example 1: array_pad([ 7, 8, 9 ], 2, 'a');
  //   returns 1: [ 7, 8, 9]
  //   example 2: array_pad([ 7, 8, 9 ], 5, 'a');
  //   returns 2: [ 7, 8, 9, 'a', 'a']
  //   example 3: array_pad([ 7, 8, 9 ], 5, 2);
  //   returns 3: [ 7, 8, 9, 2, 2]
  //   example 4: array_pad([ 7, 8, 9 ], -5, 'a');
  //   returns 4: [ 'a', 'a', 7, 8, 9 ]

  var pad = [],
    newArray = [],
    newLength,
    diff = 0,
    i = 0;

  if (Object.prototype.toString.call(input) === '[object Array]' && !isNaN(pad_size)) {
    newLength = ((pad_size < 0) ? (pad_size * -1) : pad_size);
    diff = newLength - input.length;

    if (diff > 0) {
      for (i = 0; i < diff; i++) {
        newArray[i] = pad_value;
      }
      pad = ((pad_size < 0) ? newArray.concat(input) : input.concat(newArray));
    } else {
      pad = input;
    }
  }

  return pad;
}