随笔分类 - TypeScript
摘要：For example, you have an object `A`, you want to extend it and modify some prop; then create a new interface B: export interface B extends Omit<A, 'x'
阅读全文
摘要：we're going to dive deep into a more complex example in which we combine mapped types, key remapping, template literal types, and indexed access types
阅读全文
摘要：In this lesson, we're going to explore template literal types, another powerful feature of TypeScript's type system. Template literal types have the s
阅读全文
摘要：A const assertion is a special type assertion that uses the const keyword instead of a specific type name. When using a const assertion on an object l
阅读全文
摘要：In this lesson, we're going to look at how to perform null checks with assertion functions. We're going to assert that a nullable value doesn't hold t
阅读全文
摘要：This lesson introduces assertion functions which let us narrow the type of a variable or property for the remainder of the containing scope. We're goi
阅读全文
摘要：In this lesson, we'll go over TypeScript's unknown type. The unknown type is the type-safe counterpart of the any type. Both unknown and any are so-ca
阅读全文
摘要：This lesson introduces the ?? operator which is known as nullish coalescing. The ?? operator produces the value on the right-hand side if (and only if
阅读全文
摘要：This lesson introduces the ?. operator which is known as optional chaining. We're going to look at how we can use ?. to safely descend into an object
阅读全文
摘要：const items = [ 'Sojourner', 'Opportunity', 'Spirit', 'Curiosity', 'Perseverance', ] const formatter = new Intl.ListFormat('en', { style: 'long', type
阅读全文
摘要：TypeScript can infer the type of a variable by looking at the data assigned to it. It also allows you to create a reusable type that it has inferred a
阅读全文
摘要：You can use the non-null assertion operator in TypeScript to take a typed variable and remove the undefined and null types from it. In this lesson, we
阅读全文
摘要：In this lesson, you will learn how to extend a class's functionality through typescript decorators. Decorators provide a way to add both annotations a
阅读全文
摘要：function somethingRisky() {} try { somethingRisky() } catch(err: unknown) { if (err instanceof Error) { console.log(err.stack) } else { console.log(er
阅读全文
摘要：Typescript v3.9 introduces the @ts-expect-error assertion added to TypeScript 3.9. This assertion is more descriptive than @ts-ignore because, rather
阅读全文
摘要：type Corner = `${'top' | 'bottom'}-${ 'left' | 'right'}` type VerticalAlignment = "top" | "middle" | "bottom"; type HorizontalAlignment = "left" | "ce
阅读全文
摘要：...T: type Foo<T extends any[]> = [boolean, ...T, boolean] In previous typescript version, you can only put '...T' to the last element of array. Put n
阅读全文
摘要：class Foo { #name; constructor(rawName?: string) { this.#name = rawName ?? (no name) } log() { console.log(this.#name) } } Checking 'rawName' is nulli
阅读全文
摘要：Sometime when you create a library, you want types create automatcially for you, instead of typing all the types information by yourself. // tsconfig.
阅读全文
摘要：In lodash, you can use 'mixin' to create a new function on lodash object. import * as _ from 'lodash'; _.chunk([1, 2, 3, 4], 2); // [[1,2], [3,4]] _.m
阅读全文
浙公网安备 33010602011771号