Bump to v3.0.0.

internal/isIndex.js

@@ -0,0 +1,22 @@
+/**
+ * Used as the maximum length of an array-like value.
+ * See the [ES spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength)
+ * for more details.
+ */
+var MAX_SAFE_INTEGER = Math.pow(2, 53) - 1;
+
+/**
+ * Checks if `value` is a valid array-like index.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
+ * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
+ */
+function isIndex(value, length) {
+  value = +value;
+  length = length == null ? MAX_SAFE_INTEGER : length;
+  return value > -1 && value % 1 == 0 && value < length;
+}
+
+export default isIndex;