Published Feb 16, 2022
[
yarn init
yarn add -D typescript
yarn run tsc --init
yarn add -D ts-node-dev
"scripts": {
"dev": "ts-node-dev --respawn --transpile-only index.ts"
},
yarn run dev
yarn add eslint --dev
yarn create @eslint/config
yarn add -D eslint-config-standard
yarn add -D @typescript-eslint/eslint-plugin
yarn add -D @typescript-eslint/parser
yarn add -D eslint-plugin-import
yarn add -D eslint-plugin-node
yarn add -D eslint-plugin-promise
"root": true
let cats: string[] = ["Bob", "Willy", "Mini"];
// add to end
cats.push("cat");
// remove from the end
let cat: string = cats.pop();
// remove from beginning
let cat: string = cats.shift();
//add to beginning
cats.unshift("cat");
// loop
for (let cat of cats) {
console.log(cat);
}
// clone
[...cats];
Array.from(cats);
let h: { [index: string]: number } = { a: 1, b: 2 };
// value in hash
"a" in h;
// number of keys
Object.keys(h).length;
// loop
for (let key in h) {
console.log(key);
console.log(h[key]);
}
let s: Set<string> = new Set<string>();
s.add("s");
console.log(s.has("s"));
s.delete("s");
Infinity;
boolean;