Classes Blueprint to create an object with some fields (values) and methods (functions) to represent a 'thing'. class Vehicle { drive(): void { console.log('chugga chugga'); } honk(): void { console.log('beep'); } } class Car extends Vehic…

Interfaces Creates a new type, describing the property names and value types of an object 例えば、今まで学んだことを利用して次のように型定義を行うと、コードが長くなってしまって可読性も低くなる。 const oldCivic = { name: 'civic', year: 200,…

TSでarrayを扱う上で重要なポイント TS can do type inference when extracting values from an array TS can prevent us from adding incompatible values to the array We can get help with map, forEach, reduce, functions Flexible - arrays can still…

ファンクション周りでのannotations/inference使い分け Type annotations for functions Code we add to tell TS what type of arguments a function will receive and what type of values it will return. Type inference for functions TS tries to figur…

重要な概念を2つほど。 Type annotations / Type inference Type annotations Code we add to tell TypeScript what type of value a variable will refer to Type inference TypeScript tries to figure out what type of value a variable refers to 前者…