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Start your free trialKayc M
12,593 PointsCan't log map using template literals, why?
let joe = { name: 'joe', age: 20},
ann = {name: 'ann', age: 20 };
let classroom = new Map()
classroom.set('joe', joe)
classroom.set('ann', ann)
console.log('print map: ', classroom)
output:
// print map: Map(2) {
// 'joe' => { name: 'joe', age: 20 },
// 'ann' => { name: 'ann', age: 20 }
// }
console.log(`print map: ${classroom}`)
output:
// print map: [object Map]
2 Answers
Steven Parker
231,236 PointsModern browsers may evaluate the arguments to the "log" method and invoke a special conversion designed to display that type of object, but the template string relies on the object's own string conversion method.
So:
console.log(`print map: ${classroom}`); // is equivalent to...
console.log('print map: ' + classroom.toString());
Kayc M
12,593 PointsBut why does concatenating without "toString" have the same result
console.log('print map: ' + classroom);
output:
// print map: [object Map]
Steven Parker
231,236 PointsConcatenating a non-string onto a string also invokes the built-in (toString) conversion. What the browser does for you when it is a separate argument is a new feature above and beyond the language itself, and not long ago in previous versions would have looked the same as the others.