intersection$

Obtain entries present in both maps.

Alternatives: intersection, intersection$.
Similar: union, intersection, difference, symmetricDifference, isDisjoint.

function intersection$(x, y, fc)
// x:  a map (updated)
// y:  another map
// fc: combine function (a, b)

const map = require('extra-map');

var x = new Map([['a', 1], ['b', 2], ['c', 3], ['d', 4]]);
var y = new Map([['b', 20], ['c', 30], ['e', 50]]);
map.intersection$(x, y);
// → Map(2) { 'b' => 2, 'c' => 3 }

x;
// → Map(2) { 'b' => 2, 'c' => 3 }

var x = new Map([['a', 1], ['b', 2], ['c', 3], ['d', 4]]);
var y = new Map([['b', 20], ['c', 30], ['e', 50]]);
map.intersection$(x, y, (a, b) => b);
// → Map(2) { 'b' => 20, 'c' => 30 }

References

• Data.Set.intersection: Haskell
• Set.intersection: Python
• _.intersection: lodash
• _.intersectionBy: lodash
• _.intersectionWith: lodash
• Array.intersect: sugarjs