better-modifications.md

better modifications Map and Set

This feature makes breaking change, not included in breaking-free version

When a map or set is frozen by Object.freeze(), sealed by Object.seal() or prevented extentions by Object.preventExtensions() or Reflect.preventExtensions(),

We also change returning of Map.set and the Set.add, they will return the given value like a assignment expression.

Usage

import 'https://better-js.fenz.land/src/map-and-set/modifications.js';

const map= new Map();

map.set( 0, 1, ); // returns 1

const set= new Set();

set.add( 3, ); // returns 3

const frozenMap= Object.freeze( new Map( [...], ), );

frozenMap.set( ... );    // throw TypeError(cannot modify a frozen map)
frozenMap.delete( ... ); // throw TypeError(cannot modify a frozen map)
frozenMap.clear();       // throw TypeError(cannot modify a frozen map)

const frozenSet= Object.freeze( new Set( [...], ), );

frozenSet.add( ... );    // throw TypeError(cannot modify a frozen set)
frozenSet.delete( ... ); // throw TypeError(cannot modify a frozen set)
frozenSet.clear();       // throw TypeError(cannot modify a frozen set)