Add some more documentation.

Author: beefancohen

src/rules/img-uses-alt.js

@@ -15,6 +15,7 @@ const errorMessage = 'img elements must have an alt tag.';
 module.exports = context => ({
   JSXOpeningElement: node => {
     const type = node.name.name;
+    // Only check img tags.
     if (type !== 'img') {
       return;
     }

src/util/getAttributeValue.js

@@ -1,5 +1,13 @@
 'use strict';
 
+/**
+ * Returns the value of a given attribute.
+ * Different types of attributes have their associated
+ * values in different properties on the object.
+ *
+ * This function should return the most *closely* associated
+ * value with the intention of the JSX.
+ */
 const getAttributeValue = attribute => {
   if (attribute.value === null) {
     return null;

src/util/hasAttribute.js

@@ -2,6 +2,14 @@
 
 import getAttributeValue from './getAttributeValue';
 
+/**
+ * Returns the value of the attribute or false, indicating the attribute
+ * is not present on the JSX opening element. This skips over spread attributes
+ * as the purpose of this linter is to do hard checks of explicit JSX props.
+ *
+ * This treats undefined values as missing props, as they will not be used for
+ * rendering on elements that live closest to the DOM (pure html JSX elements).
+ */
 const hasAttribute = (attributes, attribute) => {
   let value = false;
 

src/util/isHiddenFromScreenReader.js

@@ -2,6 +2,12 @@
 
 import hasAttribute from './hasAttribute';
 
+/**
+ * Returns boolean indicating that the aria-hidden prop
+ * is present or the value is true.
+ *
+ * <div aria-hidden /> is equivalent to the DOM as <div aria-hidden=true />.
+ */
 const isHiddenFromScreenReader = attributes => {
   const hasAriaHidden = hasAttribute(attributes, 'aria-hidden');
   return hasAriaHidden && (hasAriaHidden === true || hasAriaHidden === null);

src/util/isInteractiveElement.js

@@ -18,6 +18,12 @@ const interactiveMap = {
   textarea: () => true
 };
 
+/**
+ * Returns boolean indicating whether the given element is
+ * interactive on the DOM or not. Usually used when an element
+ * has a dynamic handler on it and we need to discern whether or not
+ * it's intention is to be interacted with on the DOM.
+ */
 const isInteractiveElement = (tagName, attributes) => {
   if (interactiveMap.hasOwnProperty(tagName) === false) {
     return false;