Files
30-seconds-of-code/snippets/shank.md
Mathias Bynens 8ee50178f3 Avoid confusing prototype methods for static methods
Correct: `Array.from()` (it’s a static method)
Incorrect: `Array.join()` (doesn’t exist; it’s a prototype method)

This patch uses the common `#` syntax to denote `.prototype.`.
2018-09-28 15:44:12 -04:00

1.0 KiB

shank

Has the same functionality as Array.prototype.prototype.splice(), but returning a new array instead of mutating the original array.

Use Array.prototype.slice() and Array.prototype.concat() to get a new array with the new contents after removing existing elements and/or adding new elements. Omit the second argument, index, to start at 0. Omit the third argument, delCount, to remove 0 elements. Omit the fourth argument, elements, in order to not add any new elements.

const shank = (arr, index = 0, delCount = 0, ...elements) =>
  arr
    .slice(0, index)
    .concat(elements)
    .concat(arr.slice(index + delCount));
const names = ['alpha', 'bravo', 'charlie'];
const namesAndDelta = shank(names, 1, 0, 'delta'); // [ 'alpha', 'delta', 'bravo', 'charlie' ]
const namesNoBravo = shank(names, 1, 1); // [ 'alpha', 'charlie' ]
console.log(names); // ['alpha', 'bravo', 'charlie']