cell/docs/library/array.md

title, description, weight, type

title	description	weight	type
array	Array creation and manipulation	30	docs

The array function and its methods handle array creation and manipulation.

Creation

array(number)

Create an array of specified size, filled with null.

array(3)  // [null, null, null]

array(number, initial)

Create an array with initial values.

array(3, 0)           // [0, 0, 0]
array(3, i => i * 2)  // [0, 2, 4]

array(array)

Copy an array.

var copy = array(original)

array(array, from, to)

Slice an array.

array([1, 2, 3, 4, 5], 1, 4)  // [2, 3, 4]
array([1, 2, 3], -2)          // [2, 3]

array(array, another)

Concatenate arrays.

array([1, 2], [3, 4])  // [1, 2, 3, 4]

array(object)

Get keys of an object.

array({a: 1, b: 2})  // ["a", "b"]

array(text)

Split text into grapheme clusters.

array("hello")  // ["h", "e", "l", "l", "o"]

array(text, separator)

Split text by separator.

array("a,b,c", ",")  // ["a", "b", "c"]

array(text, length)

Split text into chunks.

array("abcdef", 2)  // ["ab", "cd", "ef"]

Methods

array.for(arr, fn, reverse, exit)

Iterate over elements.

array.for([1, 2, 3], function(el, i) {
  log.console(i, el)
})

// With early exit
array.for([1, 2, 3, 4], function(el) {
  if (el > 2) return true
  log.console(el)
}, false, true)  // prints 1, 2

array.find(arr, fn, reverse, from)

Find element index.

array.find([1, 2, 3], 2)              // 1
array.find([1, 2, 3], x => x > 1)     // 1
array.find([1, 2, 3], x => x > 1, true) // 2 (from end)

array.filter(arr, fn)

Filter elements.

array.filter([1, 2, 3, 4], x => x % 2 == 0)  // [2, 4]

array.reduce(arr, fn, initial, reverse)

Reduce to single value.

array.reduce([1, 2, 3, 4], (a, b) => a + b)      // 10
array.reduce([1, 2, 3, 4], (a, b) => a + b, 10)  // 20

array.sort(arr, select)

Sort array (returns new array).

array.sort([3, 1, 4, 1, 5])  // [1, 1, 3, 4, 5]

// Sort by field
array.sort([{n: 3}, {n: 1}], "n")  // [{n: 1}, {n: 3}]

// Sort by index
array.sort([[3, "c"], [1, "a"]], 0)  // [[1, "a"], [3, "c"]]

Map with array()

The array(arr, fn) form maps over elements:

array([1, 2, 3], x => x * 2)  // [2, 4, 6]

array([1, 2, 3], function(el, i) {
  return el + i
})  // [1, 3, 5]