@labdigital/toolkit

This package contains a set of common utility functions we use for most of our typescript projects. It is unopinionated, should have almost no dependencies and is meant to be used in any project.

Installation

pnpm add @labdigital/toolkit

API

isValue (function)

Utility for lists to ensure there are no empty values.

const products = [
	{ id: "a", price: { centAmount: 20 } },
	{ id: "b", price: null },
	{ id: "c", price: { centAmount: 30 } },
];
products
	.map((x) => x.price)
	.filter(isValue)
	.map((p) => p.centAmount)[
	// results in
	(20, 30)
];

unique (function)

Filter utility to filter out duplicate values

const names = ["john", "john", "jane"].filter(unique); // ['john', 'jane']

uniqueBy (function)

groupByMap (function)

Groups a list based on a callback. Returns a Map where the keys are the result of the callback.

groupByMap(
  [{age: 18, name: 'John'}, {age: 18, name: 'Joe'}, {age: 16, name: 'Jack'}],
  p => p.age,
)

// results in
Map {
 16: [{age: 16, name: 'Jack'}],
 18: [{age: 18, name: 'John'}, {age: 18, name: 'Joe'}],
}

groupBy (function)

Groups a list based on a callback. Returns a Map where the keys are the result of the callback.

groupBy(
  [{age: 18, name: 'John'}, {age: 18, name: 'Joe'}, {age: 16, name: 'Jack'}],
  p => p.age,
)

// results in
[
 [16, [{age: 16, name: 'Jack'}]],
 [18, [{age: 18, name: 'John'}, {age: 18, name: 'Joe'}]],
]

findFirst (function)

Finds the first item in a list of items by a list of ids.

const products = [
{id: 'a', price: 1},
{id: 'b', price: 1},
{id: 'c', price: 1}
]
findFirst(['x', 'b'], products, p => p.id) // {id: 'b', price: 1}


### `range` (function)

Creates a range of numbers, staring at `start` and ending at `end` .

```ts
range({start: 0, end: 3}) // [0, 1, 2]
range({start: 1, end: 3}) // [1, 2]

zip (function)

Merges two arrays, creating a single array with tuples from both arrays.

const a = [1, 2, 3];
const b = ["a", "b", "c"];

zip(a, b); // [[1, 'a'], [2, 'b'], [3, 'c']]

getLocalizedValue (function)

Attempts to find a matching value for the provided locale by trying the given locale and its language tag, followed by locale without subtags and then by any additional fallback locales specified.

It performs both an exact case-sensitive match and a case-insensitive match to ensure compatibility with different case conventions. Notably, if a specific locale (e.g., 'en-GB') does not have a direct match, the function will try to fall back to a more general locale (e.g., 'en') before moving on to the next fallback locales.

// Define a map of localized values
const greetings = {
	en: "Hello",
	"en-US": "Howdy",
	fr: "Bonjour",
};

// Get localized value for British English without an explicit entry, falling
// back to generic English
getLocalizedValue(greetings, "en-GB");

// Get localized value for American English specifically
getLocalizedValue(greetings, "en-US");

// Attempt to get a localized value for an unsupported locale with fallbacks
getLocalizedValue(greetings, "es", "en");

sum (function)

Sums the values of a list of objects calculated by a callback.

sum([{ price: 1 }, { price: 2 }], (x) => x.price); // 3

byMin (function)

Reducer callback to find object with some minimum value.

[{ price: 1 }, { price: 2 }].reduce(byMin((x) => x.price)); // {price: 1}

byMax (function)

Reducer callback to find object with some maximum value.

[{ price: 1 }, { price: 2 }].reduce(byMax((x) => x.price)); // {price: 2}

clamp (function)

Clamps the value between min and max.

I.e. returns min if value < min, or max if value > max, or the value itself otherwise.

roundHalfEven (function)

Rounds a number to the nearest integer using the "half to even" strategy, also known as "bankers' rounding". This method minimizes bias in rounding over a large set of numbers. When the fractional part of the number is exactly 0.5, it rounds to the nearest even number.

Parameters:

• value (number) - The number to round.

// When rounding 2.5, it rounds to 2, because 2 is even
roundHalfEven(2.5); // Returns: 2

// When rounding 3.5, it rounds to 4, because 4 is even
roundHalfEven(3.5); // Returns: 4

roundHalfUp (function)

Rounds a number to the nearest integer using the "half up" strategy. This method rounds up when the fractional part of the number is 0.5 or greater. It's the most common form of rounding.

Parameters:

• value (number) - The number to round.

roundHalfUp(2.5); // Returns: 3

roundHalfUp(2.4); // Returns: 2

roundHalfDown (function)

Rounds a number to the nearest integer using the "half down" strategy. This method rounds down when the fractional part of the number is exactly 0.5, contrary to the "half up" method.

Parameters:

• value (number) - The number to round.

roundHalfDown(2.5); // Returns: 2

roundHalfDown(2.6); // Returns: 3

pruneObject (function)

Removes all undefined properties

pruneObject({
	a: 1,
	b: undefined,
});
// { a: 1 }

pick (function)

Pick a subset of items from an object

Parameters:

• base (T) - The object
• keys (K[]) - A list of keys to pick

returns: Pick<T, K>

pick({ a: 1, b: 2, c: 3 }, "a", "c"); // { a: 1, c: 3 }

objectMap (function)

Transforms an object using the given value and or key transformers.

objectMap(
	{
		a: 1,
		b: 2,
		c: 3,
	},
	{
		getKey: (key, value) => key.toUpperCase(),
		getValue: (value, key) => value * 2,
	},
); // { A: 2, B: 4, C: 6 }

createObjectHash (function)

Generates a deterministic key for an object ignoring the order of the fields.

JSON stringifies the object and generates a base64 SHA-256 hash. The keys of the object are sorted in order to get a deterministic key.