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$ curl repovive.com/roadmaps/javascript/introduction-to-typescript/type-inference

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$ curl repovive.com/roadmaps/javascript/introduction-to-typescript/type-inference

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Type Inference - Introduction to TypeScript | JavaScript | Repovive

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JavaScript22 sections · 783 units18h total

Open in Course

Type Inference

Let TypeScript figure it out

TypeScript infers types from assignments. You don't need to annotate everything.

let count = 10;        // inferred: number
let message = "hello"; // inferred: string
const items = [1, 2];  // inferred: number[]

count = "ten"; // Error! TypeScript knows count is a number

Annotate when inference isn't clear or for function parameters.