TypeScript Constant

TypeScript use const to define a constant variable and readonly to define a constant class property.

Example

const UNIT_SUFFIXES = {
    'milliseconds': 'ms',
    'seconds': 's',
};


class Foo {
    private static readonly MY_SPECIAL_NUMBER = 5;

    bar() {
        return 2 * Foo.MY_SPECIAL_NUMBER;
    }
}

Naming

Use UPPER_SNAKE_CASE per google style guide

References

• https://www.typescriptlang.org/docs/handbook/variable-declarations.html#let-vs-const
• https://stackoverflow.com/questions/46561155/difference-between-const-and-readonly-in-typescript
• https://google.github.io/styleguide/tsguide.html#identifiers-constants