Split array into chunks by size or certain condition.
- Minimal APIs
- Written in TypeScript
- Actively maintained
- Fully coverage tests
- Inspired from Ruby chunk
$ npm install chunk-arrconst { chunkBy } = require('chunk-arr');
chunkBy([3, 1, 4, 1, 5, 9, 2, 6], n => n % 2);
// [ [3, 1], [4], [1, 5, 9], [2, 6] ]Like lodash/chunk, split the array into chunks of size. If array can not be split evenly, the final chunk will be the remaining elements.
- Require:
true - Type:
any[]
The array to process
- Require:
false - Type:
number - Default:
1
The size of each chunk. Return empty array if size smaller than 1.
Note: The size will be converted to the largest number that smaller than size by Math.floor.
Example:
const { chunk } = require('chunk-arr');
// or
// const chunk = require('chunk-arr').default;
const chars = ['a', 'b', 'c', 'd', 'e'];
console.log(chunk(chars));
// Output: [ ['a'], ['b'], ['c'], ['d'], ['e'] ]
console.log(chunk(chars, 2.7));
// Output: [ ['a', 'b'], ['c', 'd'], ['e'] ]Iterate over array elements, chunking them together based on the returned value of func.
- Require:
true - Type:
T[]
The array to process
- Require:
true - Type:
(element: T, index: number): U
The function used to chunk array based on its return value. It takes two arguments: the current element is iterating and its index
Example:
- Split based on element types:
const { chunkBy } = require('chunk-arr');
const arr = [true, -3, 1, 'a', 'b', 'c'];
console.log(chunkBy(arr, e => typeof e));
// Output: [ [true], [-3, 1], ['a', 'b', 'c'] ]- Split strings by their sizes:
const { chunkBy } = require('chunk-arr');
const arr = ['Lorem', 'Ipsum', 'is', 'simply', 'dummy', 'text'];
console.log(chunkBy(arr, s => s.length));
// Output: [ ['Lorem', 'Ipsum'], ['is'], ['simply', 'dummy'], ['text'] ]This method splits the array between adjacent elements if the func receives those elements returns false.
- Require:
true - Type:
Array<T>
The array to process
- Require:
true - Type:
(previous: T, current: T): boolean
The function, which receives the two adjacent elements alternatively, splits array between them if it returns false.
Example:
- Split array into non-decreasing chunks:
const { chunkWhile } = require('chunk-arr');
const nums = [0, 9, 2, 2, 3, 2, 7, 5, 9, 5];
console.log(chunkWhile(nums, (prev, curr) => prev <= curr));
// Output: [[0, 9], [2, 2, 3], [2, 7], [5, 9], [5]]- Convert increasing numbers into the compact string:
const { chunkWhile } = require('chunk-arr');
const nums = [1, 2, 4, 9, 10, 11, 12, 15, 16, 19, 20, 21];
console.log(chunkWhile(nums, (prev, curr) => prev + 1 === curr)
.map((chunk) => chunk.length > 2 ? `${chunk[0]}-${chunk[chunk.length - 1]}` : chunk)
.join(',')
);
// Output: '1,2,4,9-12,15,16,19-21'- Split Markdown file into sections:
const Fs = require('fs');
const { chunkWhile } = require('chunk-arr');
try {
const data = Fs.readFileSync('./README.md', 'utf8');
console.log(chunkWhile(data.split('\n'), (_, current) => !current.startsWith('#')));
} catch (error) {
console.error(error);
}
// Output:
// [
// ['# chunk-arr', ...],
// ['## Why?, ...],
// ...
// ['## Author', ...]
// ]- Nam Hoang Le
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