first

node_modules/@hapi/hoek/lib/intersect.js

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+'use strict';
+
+const internals = {};
+
+
+module.exports = function (array1, array2, options = {}) {
+
+    if (!array1 ||
+        !array2) {
+
+        return (options.first ? null : []);
+    }
+
+    const common = [];
+    const hash = (Array.isArray(array1) ? new Set(array1) : array1);
+    const found = new Set();
+    for (const value of array2) {
+        if (internals.has(hash, value) &&
+            !found.has(value)) {
+
+            if (options.first) {
+                return value;
+            }
+
+            common.push(value);
+            found.add(value);
+        }
+    }
+
+    return (options.first ? null : common);
+};
+
+
+internals.has = function (ref, key) {
+
+    if (typeof ref.has === 'function') {
+        return ref.has(key);
+    }
+
+    return ref[key] !== undefined;
+};