Reusable code with generics

Generics let a function work over many types while keeping the link between input and output. <T> is a type variable filled in when the function is called.

Worked example

How it reads

<T> is a type placeholder bound when the function is called
first(items: T[]): T returns the same type the array holds

Cloud tip: You rarely need to pass <string> explicitly; TypeScript infers T from the argument you give.

index.ts

TYPESCRIPT

type-checked, then run in your browser

Console

Run your code to see its output here.

YOUR TURN

Write a generic pair<A, B>(a: A, b: B): [A, B] and log pair("Vega", 0.03): [ 'Vega', 0.03 ].

Press Run to check your work.

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