如何根据值对象的属性从地图中删除元素

Question

myMap.set(id, {x: 10, y: 20})
myMap.delete(id)

How can I delete element from a Map based on property of value object? for example in above code instead of deleting based on key, delete based on x from value

Answer 1

You'll have to iterate over the map's entries and find the one with the value you want, then delete the associated key from the map:

 const map = new Map(); const id = 'foo'; map.set(id, {x: 10, y: 20}); console.log(map.size); const foundIdEntry = [...map.entries()] .find(([, { x }]) => x === 10); if (foundIdEntry) map.delete(foundIdEntry[0]); console.log(map.size); 

That said, if you're having to do something like this regularly, it would probably be a lot better to reconsider your data structure - you might want a Map whose keys are the x values, rather than whose keys are the IDs:

map.set(10, { id: 'foo', y: 20 });

Or, when setting a value to the map, also set a key-value pair in a separate object that maps x s to its associated id , so that you can access it in the future with plain property lookup, rather than .find :

const idsByX = {};
map.set(id, {x: 10, y: 20});
idsByX['10'] = id;