propertyOf()

propertyOf<T>(object): <Key>(key) => T[Key]

Creates a function that returns the value at the given key of object.

DEPRECATED

Use an inline arrow function (key) => obj[key] instead.

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Type Parameters

T: T extends object

The type of the object.

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Parameters

object: T

The object to query.

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Returns: <Key>(key): T[Key]

A function that returns the property value for a given key.

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Since

2.0.0

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Also known as

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

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Example

// ❌ Deprecated approach
const getValue = propertyOf({ a: 1, b: 2 });
getValue('a');  // => 1
getValue('b');  // => 2

// ✅ Recommended approach
const obj = { a: 1, b: 2 };
const getValue = (key: 'a' | 'b') => obj[key];
getValue('a');  // => 1
getValue('b');  // => 2

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How it works?

Creates a function that returns the value at path of object. Deprecated: Use an arrow function.

Native Equivalent

// ❌ propertyOf(obj)
// ✅ key => obj[key]

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Use Cases

Create property getter 📌

Create function to get property from fixed object.

#property#getter#object#accessor

const obj = { a: 1, b: 2, c: 3 };
const getValue = (key: keyof typeof obj) => obj[key];
getValue('a');  // 1
getValue('b');  // 2

Map keys to values

Convert array of keys to values.

#map#keys#values#lookup

const config = { host: 'localhost', port: 3000 };
const keys = ['host', 'port'] as const;
const values = keys.map(k => config[k]);
// ['localhost', 3000]