Initial commit

README.md

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+# do-arrays-intersect
+
+Checks only *whether* two given arrays intersect (ie. have values in common), but not *what* that intersection is exactly. This allows it to stop searching when it finds the first match, which can be much faster.
+
+## License, donations, and other boilerplate
+
+Licensed under either the [WTFPL](http://www.wtfpl.net/txt/copying/) or [CC0](https://creativecommons.org/publicdomain/zero/1.0/), at your choice. In practice, that means it's more or less public domain, and you can do whatever you want with it. Giving credit is *not* required, but still very much appreciated! I'd love to [hear from you](mailto:admin@cryto.net) if this module was useful to you.
+
+Creating and maintaining open-source modules is a lot of work. A donation is also not required, but much appreciated! You can donate [here](http://cryto.net/~joepie91/donate.html).
+
+## Example
+
+```js
+const doArraysIntersect = require("do-arrays-intersect");
+
+let arrayA = [1, 3, 4, 6, 7, 8];
+let arrayB = [2, 5, 6, 8, 9];
+
+console.log(doArraysIntersect(arrayA, arrayB)); // true
+
+let arrayC = [1, 3, 4, 6, 7, 8];
+let arrayD = [2, 5, 9, 10, 11];
+
+console.log(doArraysIntersect(arrayC, arrayD)); // false
+```
+
+## API
+
+### doArraysIntersect(arrayA, arrayB)
+
+Checks whether two arrays intersect. The equivalence function is `===`, and custom equivalence functions are not currently supported; please file an issue if you need this!
+
+The order that you specify the arrays in, does not matter.
+
+- __arrayA:__ The first array.
+- __arrayB:__ The second array.
+
+Returns a boolean indicating whether an intersection was found (`true`) or not (`false`).

example.js

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+"use strict";
+
+const doArraysIntersect = require("./");
+
+let arrayA = [1, 3, 4, 6, 7, 8];
+let arrayB = [2, 5, 6, 8, 9];
+
+console.log(doArraysIntersect(arrayA, arrayB)); // true
+
+let arrayC = [1, 3, 4, 6, 7, 8];
+let arrayD = [2, 5, 9, 10, 11];
+
+console.log(doArraysIntersect(arrayC, arrayD)); // false

index.js

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+"use strict";
+
+module.exports = function doArraysIntersect(arrayA, arrayB) {
+	let oneSet, otherArray;
+
+	if (arrayA.length > arrayB.length) {
+		oneSet = new Set(arrayA);
+		otherArray = arrayB;
+	} else {
+		oneSet = new Set(arrayB);
+		otherArray = arrayA;
+	}
+	
+	return otherArray.some((item) => oneSet.has(item));
+};

package.json

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+{
+  "name": "do-arrays-intersect",
+  "version": "1.0.0",
+  "main": "index.js",
+  "description": "Check whether arrays intersect without caring about the exact intersection, which is faster",
+  "repository": "git@git.cryto.net:joepie91/do-arrays-intersect.git",
+  "author": "Sven Slootweg <admin@cryto.net>",
+  "license": "WTFPL OR CC0-1.0"
+}