JavaScript: Truncate Map

By Xah Lee. Date: .

Here's a function that return a new map, containing only first n entries.

/* [ return a new map, containing only first n entries.
http://xahlee.info/js/js_map_truncate.html
Version 2021-05-08
] */
const xah_truncate_map =
  ((mapObj, n) =>
    new Map([...mapObj.entries()].slice(0, Math.min(...[mapObj.size, n]))));

// test
// const m = new Map([[3, "n3"], [4, "n4"], [5, "n5"]]);
// console.log(xah_truncate_map(m,2));
// Map { 3 => "n3", 4 => "n4" }

You probably want to use it with JS: Sort Map

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