Get the Preplance app for a seamless learning experience. Practice offline, get daily streaks, and stay ahead with real-time interview updates.
Get it on
Google Play
4.9/5 Rating on Store
Datadog · Typescript
Practice Typescript questions specifically asked in Datadog interviews – ideal for online test preparation, technical rounds and final HR discussions.
Questions
5
Tagged for this company + subject
Company
Datadog
View company-wise questions
Subject
Typescript
Explore topic-wise practice
Go through each question and its explanation. Use this page for targeted revision just before your Datadog Typescript round.
Source maps link compiled JavaScript back to TypeScript, so errors and logs point to your original TS files—perfect for debugging CLI tools.
// tsconfig.json
{
"compilerOptions": { "sourceMap": true, "outDir": "dist" }
}
// run Node with source-map support if neededFor complete preparation, combine this company + subject page with full company-wise practice and subject-wise practice. You can also explore other companies and topics from the links below.
You can add a fake first parameter named `this` to type the `this` context. It isn’t emitted at runtime—it’s only for type checking.
function move(this: { x: number; y: number }, dx: number, dy: number){
this.x += dx; this.y += dy;
}
const p = { x: 0, y: 0, move };
p.move(1,2);Set `baseUrl` (the root) and define `paths` mappings. This shortens import paths and avoids deep relative imports.
// tsconfig.json
{
"compilerOptions": {
"baseUrl": ".",
"paths": { "@app/*": ["src/*"] }
}
}
// import { util } from '@app/utils/util';Use “as NewK” in a mapped type to rename keys while iterating over them.
type PrefixKeys<T> = {
[K in keyof T as `app_${Extract<K, string>}`]: T[K]
};`as const` freezes property mutability at the type level and preserves literal values (e.g., `'UP'` not `string`). It often compiles to simple objects with no enum helpers, which can reduce bundle overhead.
const DIR = { Up: 'UP', Down: 'DOWN' } as const;
type Dir = typeof DIR[keyof typeof DIR]; // 'UP' | 'DOWN'