I have this map:
var map = new Map(); map.set("10/10", 0); map.set("10/11", 1); map.set("10/12", 2); { "10/10": 0, "10/11": 1, "10/12": 2, }
And I want to add this new key/value:
"10/9": 0,
How can I increase the values of all the old map elements in 1? So I get the following map:
{ "10/9": 0, "10/10": 1, "10/11": 2, "10/12": 3, }
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Answer
You can use something like this:
var map = new Map(); map.set("10/10", 0); map.set("10/11", 1); map.set("10/12", 2); function addNewItem(item, map) { map.forEach((value, key, map) => { map.set(key, value + 1); }); map.set(item, 0); return map; } const newMap = addNewItem("10/9", map); console.log(newMap);