Description
I recently got tricked by calling Object.keys() / Object.values() / Object.entries() on a Map object, and it took me a while to realize that it was wrong:
const m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log('m.size:', m.size);
// Incorrect:
console.log('Object.keys(m):', Object.keys(m)); // Array [] (empty)
console.log('Object.values(m):', Object.values(m)); // Array [] (empty)
console.log('Object.entries(m):', Object.entries(m)); // Array [] (empty)
// Correct:
console.log('Array.from(m.keys()):', Array.from(m.keys())); // Array [ "a", "b" ]
console.log('Array.from(m.values()):', Array.from(m.values())); // Array [ 1, 2 ]
console.log('Array.from(m.entries()):', Array.from(m.entries())); // Array [ Array [ "a", 1 ], Array [ "b", 2 ] ]Would you be open to add a rule detecting the incorrect usage above?
Fail
var m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log(Object.keys(m));var m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log(Object.values(m));var m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log(Object.entries(m));Pass
var m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log(Array.from(m.keys()));var m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log(Array.from(m.values()));var m = new Map();
m.set('a', 1);
m.set('b', 2);
console.log(Array.from(m.entries()));Additional Info
No response
sindresorhus / eslint-plugin-unicorn
More than 100 powerful ESLint rules
4.2k
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