@daeinc/array

Array utilities.

Installation

npm i @daeinc/array

then,

import { fillAndMap, ... } from "@daeinc/array";

Functions

accumulate

const accumulate: (arr: number[], precision?: number) => number[];

Takes in a number array and returns a new array with values accumulated. For example, the input array [1, 2, 3, 4] will return [1, 3, 6, 10]. It also takes an optional parameter precision(default=4) to compensate for float rounding error. The original values are used while summing, but the return values will be rounded.

addToArray

const addToArray: <T>(
  arr: T[],
  entry: T,
  newArrayLen: number,
  mode?: "first" | "last"
) => T[];

Adds a new element to array in-place while limiting how many to keep history. The mode first will insert at the beginning of the array.

fillAndMap

const fillAndMap: <T>(n: number, fn: (el: null, idx: number) => T) => T[];

Creates a new array with given length and maps values

getNonZeroIndices

const getNonZeroIndices: (arr: number[]) => number[];

Check for elements with non-zero values and return indices.

interpolateArray

const interpolateArray: (
  arrStart: number[],
  arrTarget: number[],
  t: number
) => number[];

Interpolates between two 1-dimensional arrays of same size.

isAllOne

const isAllOne: (arr: number[]) => boolean;

Returns true if all elements of input array is 1.

isAllZero

const isAllZero: (arr: number[]) => boolean;

Returns true if all elements of input array is 0.

isAnyOne

const isAnyOne: (arr: number[]) => boolean;

Returns true if any element of input array is 1.

isAnyZero

const isAnyZero: (arr: number[]) => boolean;

Returns true if any element of input array is 0.

objectToArray

const objectToArray: <T>(
  obj: {
    [key: string]: T;
  },
  keys: string[]
) => T[];

Convert object key-value pairs into simple array of values. Only included keys will be converted. The order is preserved.

This function can be useful when converting objects with {x, y} to [x, y], for example.

unwrapArrayOfObjects

const unwrapArrayOfObjects: <T>(
  arr: {
    [key: string]: T;
  }[],
  objKey: string
) => T[];

A helper function to get object values inside an array. All objects must have same keys present. For example, when the input array is [ {name: val1}, {name: val2} ], calling unwrapArrayOfObjects(arr, "name") will return [val1, val2].

To dos

• test

License

MIT