🎯 Sets the value at a specific path of an object.

Warning

Mutable: This function mutates the original object. Use toSet for an immutable version.

Syntax

TypeScript
import { set } from '@opentf/std';

set<T>(
  obj: T,
  path: string | unknown[],
  value: unknown | ((val: unknown) => unknown)
): T

Parameters

  • obj: The object to modify.

  • path: The path of the property to set.

  • value: The value to set, or a callback function that receives the current value and returns the new value.

Returns

The modified object.

Behavior

  • Missing intermediate branches are created automatically.

  • Existing non-object intermediates such as 0, false, '', and null are preserved. Deep writes through those values are ignored instead of overwriting them.

Examples

TypeScript
set({}, 'a', 1) //=> { a: 1 }

set({}, 'a.b', 25) //=> { a: { b: 25 } }

set({}, 'user.email', 'user@example.com') 
//=> { user: { email: 'user@example.com' } }

set({}, 'fruits[0]', 'Apple') //=> { fruits: ['Apple'] }

// Using a callback to update based on current value
set({ a: 1 }, 'a', (val) => val + 1) //=> { a: 2 }

// Automatically creates arrays if indices are used in path
set({}, 'items[2].id', 1) //=> { items: [undefined, undefined, { id: 1 }] }

// Existing falsy non-object intermediates are not replaced
set({ a: 0 }, 'a.b', 1) //=> { a: 0 }
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