So there is a little clause you may have missed:
Type checking requires spread elements to match up with a rest parameter.
Without Rest Parameter
But you can use a type assertion to go dynamic... and it will convert back to ES5 / ES3 for you:
function foo(x:number, y:number, z:number) {
console.log(x,y,z);
}
var args:number[] = [0, 1, 2];
(<any>foo)(...args);
This results in the same apply function call that you'd expect:
function foo(x, y, z) {
console.log(x, y, z);
}
var args = [0, 1, 2];
foo.apply(void 0, args);
With Rest Parameter
The alternative is that it all works just as you expect if the function accepts a rest parameter.
function foo(...x: number[]) {
console.log(JSON.stringify(x));
}
var args:number[] = [0, 1, 2];
foo(...args);
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Operators › Spread_syntax
Spread syntax (...) - JavaScript | MDN
The spread (...) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value ...
GitHub
github.com › microsoft › TypeScript › issues › 32689
Spread operator for object types and interfaces · Issue #32689 · microsoft/TypeScript
August 2, 2019 - Provide an operator to be used in both {} types and interface types which inherits a set of properties from another object type whilst also allowing for those properties to be selectively overridden.
Published Aug 02, 2019
Typescript and spread operator? - Stack Overflow
Why am i getting getting this error in Typescript Playground??? Supplied parameters donot match any signature of call target. ... Type checking requires spread elements to match up with a rest parameter. More on stackoverflow.com
Adding arbitrary attributes to object using spread operator
It’s not really a bug. If they performed excess property checks with spreading, the resulting errors would be very awkward to work around. Generally, typescript doesn’t care about excess properties. This is why Object.keys emits strings and not keyof T. More on reddit.com
4
2
April 25, 2024Spread operator
Afraid not. Javascript get syntax does not create a property that is enumerable. It can be accessed directly but won't be accessed via an object spread or a for/in loop. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get#using_getters_in_classes More on reddit.com
22
4
August 8, 2024Is there a way to set parameters for the "arguments" variable without using the spread operator?
coordinated repeat hobbies reach sense smell snails sophisticated act boat This post was mass deleted and anonymized with Redact More on reddit.com
11
5
March 20, 2024Videos
08:43
#30 Spread Operator | TypeScript Advance ES6 Features | A Complete ...
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Spread operator challenges in typescript - YouTube
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💥 The Typescript Object Spread Operator - YouTube
Spread Operator in ECMAScript. Spread Operator usage for ...
00:52
What is a "Spread operator" in JS / TS? - YouTube
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Master Spread Operator with TypeScript - YouTube
GitHub
gist.github.com › kerren › 76114345d96a676aa904839b98446668
[The spread operator] A simple example to show how it works #spread #operator #typescript · GitHub
[The spread operator] A simple example to show how it works #spread #operator #typescript - spread-operator.ts
Top answer 1 of 4
86
So there is a little clause you may have missed:
Type checking requires spread elements to match up with a rest parameter.
Without Rest Parameter
But you can use a type assertion to go dynamic... and it will convert back to ES5 / ES3 for you:
function foo(x:number, y:number, z:number) {
console.log(x,y,z);
}
var args:number[] = [0, 1, 2];
(<any>foo)(...args);
This results in the same apply function call that you'd expect:
function foo(x, y, z) {
console.log(x, y, z);
}
var args = [0, 1, 2];
foo.apply(void 0, args);
With Rest Parameter
The alternative is that it all works just as you expect if the function accepts a rest parameter.
function foo(...x: number[]) {
console.log(JSON.stringify(x));
}
var args:number[] = [0, 1, 2];
foo(...args);
2 of 4
14
I think @Fenton explains it very well but I would like to add some more documentation and possible solutions.
Solutions:
Function overload. I prefer this solution in this case because it keeps some kind of type safety and avoids ignore and any. The original method and function call does not need to be rewritten at all.
function foo(...args: number[]): void
function foo(x: number, y: number, z: number) {
console.log(x, y, z);
}
var args: number[] = [0, 1, 2];
foo(...args);
Use @ts-ignore to ignore specific line, TypeScript 2.3
function foo(x: number, y: number, z: number) {
console.log(x, y, z);
}
var args: number[] = [0, 1, 2];
// @ts-ignore
foo(...args);
Use as any.
function foo(x: number, y: number, z: number) {
console.log(x, y, z);
}
var args: number[] = [0, 1, 2];
(foo as any)(...args);
Link with documentation regarding the spread operator:
https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-1.html
Discussions regarding this:
https://github.com/Microsoft/TypeScript/issues/5296 https://github.com/Microsoft/TypeScript/issues/11780 https://github.com/Microsoft/TypeScript/issues/14981 https://github.com/Microsoft/TypeScript/issues/15375
HowToDoInJava
howtodoinjava.com › home › typescript › typescript / javascript spread operator
TypeScript / JavaScript Spread Operator (with Examples)
July 3, 2023 - The spread operator is a new addition to the features available in the JavaScript ES6 version. The spread operator is used to expand or spread an iterable or an array in Typescript or Javascript. 1. When to use the Spread Operator?
Jser
jser.dev › shorts › 2023-09-23-spread-not-sound
Spread operator in TypeScript is not sound!!
August 15, 2023 - Before TypeScript improves on this issue, just remember that spread leads to unsound type in TypeScript, it is best to explicit type the variable before spreading.
Medium
medium.com › @slamflipstrom › conditional-object-properties-using-spread-in-javascript-714e0a12f496
Conditional Object Properties Using Spread in JavaScript | by Sam Lindstrom | Medium
June 6, 2019 - The spread operator ( ... ) allows us to expand iterables into function calls, array literals, and object literals — if you’re using ES2018. Spread syntax allows for some really convenient handling and duplicating of datasets without the ...
GeeksforGeeks
geeksforgeeks.org › typescript › how-to-use-spread-operator-in-typescript
How to use Spread Operator in TypeScript ? - GeeksforGeeks
July 23, 2025 - The spread operator in TypeScript simplifies array and object manipulation by enabling easy copying, combining, and property modification.
Appsmith
community.appsmith.com › content › guide › javascript-spread-operator-what-are-those-three-dots-my-code
The Javascript Spread Operator - What Are Those Three Dots in My Code? | Appsmith Community Portal
August 29, 2023 - Yes! The spread operator can also be used with other iterable objects like strings, maps, and sets. When used with a string, it spreads each character of the string into individual elements.
Tim Mousk
timmousk.com › blog › typescript-spread-operator
How To Use The Spread Operator In TypeScript? – Tim Mouskhelichvili
March 27, 2023 - The spread operator allows to spread or expand iterable objects into individual elements.
GitBook
basarat.gitbook.io › typescript › future-javascript › spread-operator
Spread Operator | TypeScript Deep Dive
December 31, 2019 - The main objective of the spread operator is to spread the elements of an array or object.
egghead.io
egghead.io › lessons › javascript-copy-an-array-with-the-spread-operator
Create a Custom Type Based of an Object with Typescript keyof Operator | egghead.io
[00:00] For this TypeScript tip, let's imagine you have this dim object, where you have different colors, name it as primary, primary border, secondary, whatever. And you want to create a function, for example, some component that receives a prop named color, and that color can only be some type where some time is one of these keys. How can you do that? To do that, you can use the combination of two operators, typeof and keyof.
Published July 12, 2019
DEV Community
dev.to › marinamosti › understanding-the-spread-operator-in-javascript-485j
Understanding the Spread Operator in JavaScript - DEV Community
September 23, 2019 - Good article! However, I feel like it's important to mention that the spread operator does not perform a deep clone on objects, but rather a shallow copy. This means that the spread operator will copy simple values (such as integers, strings and such) but keep the same references for objects.
Marius Schulz
mariusschulz.com › blog › object-rest-and-spread-in-typescript
Object Rest and Spread in TypeScript — Marius Schulz
July 11, 2019 - Just like Object.assign(), object spread only copies over property values, which might lead to unintended behavior if a value is a reference to another object. Note that none of the code snippets in this post contain any type annotations or other TypeScript-specific constructs.
TypeScript
typescriptlang.org › docs › handbook › release-notes › typescript-3-0.html
TypeScript: Documentation - TypeScript 3.0
TypeScript 3.0 adds support to multiple new capabilities to interact with function parameter lists as tuple types. TypeScript 3.0 adds support for: Expansion of rest parameters with tuple types into discrete parameters. Expansion of spread expressions with tuple types into discrete arguments.
TypeScript
typescriptlang.org › docs › handbook › 2 › functions.html
TypeScript: Documentation - More on Functions
In TypeScript, the type annotation on these parameters is implicitly any[] instead of any, and any type annotation given must be of the form Array<T> or T[], or a tuple type (which we’ll learn about later). Conversely, we can provide a variable number of arguments from an iterable object (for example, an array) using the spread syntax.
Reddit
reddit.com › r/typescript › adding arbitrary attributes to object using spread operator
r/typescript on Reddit: Adding arbitrary attributes to object using spread operator
April 25, 2024 -
Why is it possible to add arbitrary attributes to an object? This should throw a Typescript error in my opinion.
type Params = {
limit: number;
}
// Does not work
const params: Params = {
limit: 20,
q: "john"
}
// Does work
const spreadParams: Params = {
limit: 20,
...({ q: "john" })
};
console.log(spreadParams.q);
// 'john'https://www.typescriptlang.org/play/?ssl=18&ssc=10&pln=1&pc=1#code/C4TwDgpgBACghgJzgWwM5QLxQN4CgoFQA2AlsicAFxQB2ArsgEYQIDcuAvrrgPQ9QARAPYR0NIcCgB3IQgDWuAMZCaqSWEQpU1eEjSYc+QqXJUoAJgAMAGiMEAjtQBEAKyEALGk87c+gkegy8koqalCoYAgQcAAmulo6mvpYeITEZBTUVrZpAHT5ABTYUI5Qrh5eUBwAlJzsIapCRBC5REIA5gURUbHxaLn21ex+AORuniO4QA
Top answer 1 of 3
12
It’s not really a bug. If they performed excess property checks with spreading, the resulting errors would be very awkward to work around. Generally, typescript doesn’t care about excess properties. This is why Object.keys emits strings and not keyof T.
2 of 3
2
This is apparently a known Typescript bug: https://github.com/microsoft/TypeScript/issues/39998
Convex
convex.dev › advanced › advanced concepts › spread operator
Spread Operator | TypeScript Guide by Convex
The TypeScript spread operator (...) is a handy feature that can make your code simpler and easier to read. By using it, you can take elements from arrays or properties from objects and spread them into a new array or object.
Alexey Berezin
blog.beraliv.dev › 2021-07-05-spread-in-typescript
TypeScript spread operator for 2 object types
July 5, 2021 - As I previously said, EcmaScript 6 introduced the spread operator which does the same in JavaScript which we want to achieve here. Let's have an example: ... If we have the same key in both objects, we use if from the second object. Otherwise, we get it from the first object. So let's iterate over all keys of two objects in TypeScript and check whether we have a key in second object.
Newline
newline.co › books › beginners-guide-to-typescript › spread-operator
Spread Operator - Beginners Guide to TypeScript - 33 | newline
October 21, 2020 - The spread operator faciliates three common tasks: - Lesson 33