Different types that can be used when deconstructing arrays

function f([x,y,z]) {
  // this code is functional, although x, y and z can be any type
}

Is it feasible to write code like this?

function f([x: number,y: number,z: number]) {
  // specifying x, y, and z as numbers in the function signature 
}

Answer №1

Here is the correct way to destructure an array within a list of arguments:

function f([a,b,c]: [number, number, number]) {

}

Answer №2

Absolutely, it certainly is. When working in TypeScript, handling arrays with specific types can be done effortlessly by utilizing tuples.

type StringKeyValuePair = [string, string];

By giving the array a name, you have the flexibility to manipulate it as needed:

function f(xs: [number, number, number]) {}

It's best not to assign names to the internal parameters during this process. Alternatively, you can utilize destructuring for pair-wise operations:

function f([a,b,c]: [number, number, number]) {}

Answer №3

Labels are now supported in tuple types with the introduction of TypeScript 4.0

type Interval = [from: number, to: number]

Answer №4

Here is the code snippet I was working with:

interface Node = { 
    start: string;
    end: string;
    level: number;
};

const getNodesAndCounts = () => { 
    const nodes: Node[]; 
    const counts: number[];
    // ... code goes here

return [nodes, counts];
}

const [nodes, counts] = getNodesAndCounts(); // encountered an issue with types

When using TypeScript, I faced the error message TS2349: Cannot invoke an expression whose type lacks a call signature;

nodes.map(x => { 
//some mapping logic; 
    return x;
);

To resolve this problem, I made a modification to the line as shown below:

const [nodes, counts] = <Node[], number[]>getNodesAndCounts();

Answer №5

If you're looking for an easy solution, here is a quick way to accomplish this task:

function f([x,y,z]: number[]) {}

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