[docs] Added JSDoc comments

Select.js

@@ -1,19 +1,53 @@
 'use strict';
 
+/**
+ * Return a function based on a condition.
+ * Functional alternative to switch-case.
+ * @projectname Select-Return
+ * @version 1.0.0
+ * @author Muthu Kumar (@MKRhere)
+ */
+
+/**
+ * Creates a SelectValue instance with a value and optional resolve function.
+ * Created internally from SelectIterable constructor, and not exported.
+ * @class SelectValue
+ */
 class SelectValue {
+	/**
+	 * @param {any} value - the input value
+	 * @param {function} resolve - optional resolve function
+	 * @constructs SelectIterable
+	 */
 	constructor(value, resolve) {
 		this.value = value;
-		if (resolve) this.resolve = resolve;
+		if (resolve) this.resolve = (...args) => resolve(...args, value);
 	}
 
+	/**
+	 * Default resolve prototype. Returns null when called.
+	 * Used in case a resolve is never set.
+	 * @returns {object} null
+	 * @memberof SelectValue
+	 */
 	resolve() {
 		return null;
 	}
 }
 
-// SelectValue.prototype.resolve = () => null;
-
+/**
+ * Creates a SelectIterable instance from an array.
+ * Created internally from Select.prototype.for, and not exported.
+ * @class SelectIterable
+ */
 class SelectIterable {
+	/**
+	 * @param {array} values - array created from Select.prototype.for
+	 * @param {Array<function>} tests - array of { test, consequent } objects
+	 * @param {function} tests[].test - test function
+	 * @param {function} tests[].consequent - consequent function
+	 * @constructs SelectIterable
+	 */
 	constructor(values, tests) {
 		this.values = values
 			.map(x => x instanceof SelectValue
@@ -23,7 +57,19 @@ class SelectIterable {
 		this.tests = tests;
 	}
 
+	/**
+	 * Accepts a test and consequent function each and returns a new
+	 * SelectIterable instance.
+	 * @param {Test} test - test callback function
+	 * @param {function} consequent - consequent callback function
+	 * @returns {SelectIterable} - an instance of SelectIterable
+	 * @memberof SelectIterable
+	 */
 	for(test, consequent) {
+		/* SelectIterable.prototype.for works a little
+			differently than Select.prototype.for,
+			by accumulating the tests and resolving
+			all the values when .resolve() is called */
 		return new SelectIterable(
 			this.values,
 			[ ...this.tests, { test, consequent } ]
@@ -31,6 +77,8 @@ class SelectIterable {
 	}
 
 	resolve(...args) {
+		/* When .resolve() is called, a resolved value
+			is generated for each value in the array */
 		return this.values.map(item => {
 			const resolver = this
 				.tests
@@ -38,26 +86,52 @@ class SelectIterable {
 					? x.consequent
 					: null);
 			return resolver
-				? resolver.consequent(...args, this.value)
+				? resolver.consequent(...args, item.value)
 				: null;
 		});
 	}
 }
 
+/**
+ * Creates a new Select instance.
+ * @class Select
+ * @extends {SelectValue}
+ */
 class Select extends SelectValue {
+	/**
+	 * @param {any|array} value - the value or array of values to check against
+	 * @param {function} resolve - optional resolve function
+	 * @constructs Select
+	 */
 	constructor(value, resolve) {
 		super(value, resolve);
 		this.iterable = typeof value === "object" && Symbol.iterator in value;
 	}
 
+	/**
+	 * Accepts a test and consequent function each and returns a new
+	 * Select or SelectIterable instance.
+	 * @param {function} test - test callback function
+	 * @param {function} consequent - consequent callback function
+	 * @returns {Select|SelectIterable} - Returns a SelectIterable instance
+	 * if value was array, or a Select instance otherwise
+	 * @memberof Select
+	 */
 	for(test, consequent) {
 		if (this.iterable) {
+			/* If the value passed to the constructor is
+				an array, initialise a new SelectIterable
+				with the array and { test, consequent } pair
+				and return */
 			return new SelectIterable(
 				Array.from(this.value),
 				[ { test, consequent } ],
 			);
 		}
 		if (test(this.value)) return new Select(this.value, consequent);
+		/* If the test doesn't pass, just pass the Select
+			instance along the chain until a test passes,
+			or .resolve() is called */
 		return this;
 	}
 }