To check if a string contains a substring in TypeScript, use the includes() method: const text = "TypeScript is awesome"; console.log(text.includes("awesome")); // true console.log(text.includes("Java")); // false This method is case-sensitive. For case-insensitive checks: console.lo...
--src: Input directory which contains .ts files --out: Output directory which sanitizer script will be saved to --strict: Whether use strict mode. In strict mode, script does not check string value can be converted to number or boolean ...
export type BasicPrimitive = number | string | boolean; export function doStuff(value: BasicPrimitive) { if (Math.random() < 0.5) { return undefined; } return value; } We can see what happens in the TypeScript playground. While we might want TypeScript to display the return type of doSt...
TypeScript will first check whetherpackage.jsoncontains a"tsconfig"field, and if it does, TypeScript will try to load a configuration file from that field. If neither exists, TypeScript will try to read from atsconfig.jsonat the root. This is similar to...
Comparing number- and string-based enums A subtle difference between number-based enums and string-based enums is that number-based enums have reverse mapping for number-valued members. Reverse mapping allows us to check if a given value is valid in the context of the enum. To better under...
(You can use npm info <my-package> to check for the existence of the <my-package> package.) Your package should have this structure: FilePurpose index.d.ts This contains the typings for the package. <my-package>-tests.ts This contains sample code which tests the typings. This code ...
Whichever side you put this decorator on will be the owning side of the relationship. The owning side of a relationship contains a column with a foreign key in the database.Relations in ESM projectsIf you use ESM in your TypeScript project, you should use the Relation wrapper type in ...
type Primitive = number | string | boolean; // to satisfy Remove<{a : string;}, "a"> === {} type ConvertPrimitiveToEmptyType<T> = T extends Primitive ? {} : T; // if T contains a key with name <KeyName> at level 1, proceed recursively ...
A top level node_modules folder contains library source code and its contents are excluded from the project context by default Every other .js, .jsx, .ts, and .tsx file is possibly one of your own source files and must be included in project contextIn...
import React from 'react'; import { shallow } from 'enzyme'; import App from './App'; it('renders welcome message', () => { const wrapper = shallow(<App />); const welcome = <h2>Welcome to React</h2>; // expect(wrapper.contains(welcome)).to.equal(true); expect(wrapper.contain...