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ViewsSpread Operator - TypeScript
I'm trying to pass an array as an argument with Spread operator but something is going wrong.
function addThreeNumbers(x:number, y:number, z:number){
console.log(x+y+z)
}
const args: number[] = [2,6,4]
addThreeNumbers(...args)
·
Juan Pablo Isaza
2 answers
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It's exactly as the error says:
A spread argument must either have a tuple type or be passed to a rest parameter.
So either make args a tuple, such as with as const so it doesn't get widened to number[]:
const args = [2, 6, 4] as const;
Or make the parameters a rest parameter instead:
function addThreeNumbers(...args: number[]) {
console.log(args[0] + args[1] + args[2])
// or args.reduce((a, b) => a + b, 0)
}
·
Juan Pablo Isaza
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For TypeScript to correctly predict what argument types are going to spread into the parameter, you will have to change the args variable type into a tuple as follows:
const args: [number, number, number] = [2, 6, 4];
·
Juan Pablo Isaza
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