Can you explain the meaning of <T, U = T> in typescript terms?

While I'm comfortable with the syntax <T, U> and its use, I find myself puzzled by the syntax <T, U = T>. I've combed through the TypeScript documentation without success in locating any information on this. Any recommendations for further reading would be greatly appreciated. Thank you.

Despite my efforts to research the TypeScript documentation, I have been unable to locate any references to <T, U = T>.

Answer №1

This code snippet demonstrates how default values can be provided for generic types in TypeScript.

Here's an example to illustrate the concept:

// Define a generic function with type parameter T
function myFunc<T>() {}

// Specify a default type of string for T if not explicitly provided
function myFunc<T = string>() {}

// Define a generic function with two type parameters, T and U
function myFunc<T, U>() {}

// Set a default type of string for U if it is not specified
function myFunc<T, U = string>() {}

// If type U is not provided explicitly, default to type T
function myFunc<T, U = T>() {}

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