CODEWITHSUNDEEP
typescripttypesmergedeclaration
snowfrogdev
snowfrogdev

Reputation: 6873

TypeScript definition for function that merges two objects

Given a function that takes in two objects of different types, object A and object B, merges both objects into one and returns that merged object:

/**  
 * @description Merge the contents of two objects into a single object
 * @param {Object} target The target object of the merge
 * @param {Object} ex The object that is merged with target
 * @return {Object} The target object
 * @example
 * var A = {a: function() {console.log(this.a}};
 * var B = {b: function() {console.log(this.b}};
 *
 * pc.extend(A,B);
 * A.a();
 * // logs "a"
 * A.b();
 * // logs "b"
 */

This is what i came up with but somehow I'm not sure this is right:

function extend<T>(target: T, ex: T): T

What should the function declaration look like? Should I be using generic types for this? How do I define the merged type being returned?

Upvotes: 0

Views: 83

Answers (1)

Jeff Mercado
Jeff Mercado

Reputation: 134841

You're describing an Intersection Type, a combination of multiple types. Your scenario is even explained in the documentation.

In your case, you'll need to introduce a second generic parameter, to represent the other type. Your signature should look like this:

function extend<T, U>(target: T, ex: U): T & U

Upvotes: 3

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