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fromPairs()

fromPairs<Key, Value>(pairs): Record<Key, Value>

Creates an object from an array of key-value pairs.

💎 Why is this a Hidden Gem?

Transform key-value tuples into fully typed objects in a single call.

DEPRECATED

Use Object.fromEntries(pairs) directly instead.

Reason:
Native equivalent method now available

Type Parameters​

Key: Key extends PropertyKey​

The type of object keys.

Value: Value​

The type of object values.

Parameters​

pairs: [Key, Value][]​

The key-value pairs.

Returns: Record<Key, Value>​

A new object composed from the key-value pairs.

See Also​

Since​

2.0.0

Also known as​

fromEntries (Effect) · fromPairs (Lodash, es-toolkit, Remeda, Ramda) · ❌ (Radashi, Modern Dash, Antfu)

Example​

const pairs: [string, number][] = [['a', 1], ['b', 2], ['c', 3]];

// ❌ Deprecated approach
const obj = fromPairs(pairs);
console.log(obj); // { a: 1, b: 2, c: 3 }

// ✅ Recommended approach
const objNative = Object.fromEntries(pairs);
console.log(objNative); // { a: 1, b: 2, c: 3 }

How it works?​

Creates an object from key-value pairs. Deprecated: Use Object.fromEntries() directly (ES2019).

Native Equivalent​

// ❌ fromPairs(pairs)
// ✅ Object.fromEntries(pairs)

Use Cases​

Convert entries to object 📌​

Create an object from key-value pairs.

const pairs = [["a", 1], ["b", 2], ["c", 3]];
Object.fromEntries(pairs);
// => { a: 1, b: 2, c: 3 }

Build config from array​

Transform configuration arrays into objects.

const config = [["host", "localhost"], ["port", 3000]];
Object.fromEntries(config);
// => { host: "localhost", port: 3000 }

Convert Map to object​

Transform a Map into a plain object.

const map = new Map([["key1", "value1"], ["key2", "value2"]]);
Object.fromEntries(map);
// => { key1: "value1", key2: "value2" }

Build query params from active filters​

Construct a query parameter object from a list of active filter selections. Common in search UIs where filters are toggled on/off dynamically.

const activeFilters = [
  { key: "category", value: "electronics" },
  { key: "minPrice", value: "50" },
  { key: "inStock", value: "true" },
];

const queryParams = fromPairs(activeFilters.map((f) => [f.key, f.value]));
// => { category: "electronics", minPrice: "50", inStock: "true" }

const url = `/api/products?${new URLSearchParams(queryParams)}`;
// => "/api/products?category=electronics&minPrice=50&inStock=true"