With Array, I can use array[index]++
But with Map, I only know map.set(index,map.get(index)+1)
I think it looks bad, and if index is a long name function, I have to split it into two lines.
Is there a more concise way to implement map[index]++
1 Answer
I could only suggest a helper function, like
function update(map, key, fn) {
return map.set(key, fn(map.get(key), key));
}
update(table, index, i=>i+1);
There is no syntactic sugar for assignments, and therefore no shorthand assignments either.
If your keys are strings, you could employ a Proxy with suitable traps to disguise the update as a property access.
const mapMethods = {
has: Function.prototype.call.bind(Map.prototype.has),
get: Function.prototype.call.bind(Map.prototype.get),
set: Function.prototype.call.bind(Map.prototype.set),
};
function asObject(map) {
return new Proxy(map, mapMethods);
}
asObject(table)[index]++;
Disclaimer: Please don't do that. It's scary.
Is there a more concise wayno (excluding the obvious -Map.prototype.incr = function(x) { this.set(x, this.get(x) + 1); })