[fix] - Convert some arrow syntax functions to function syntax and add better documentation.

I decided to convert *all* of the util functions from arrow syntax to
function syntax for consistency and readability. This is where all of
the shared logic really lies and it helps with grokking. Since we are
already at one function per file, it doesn’t make the code more
readable to keep inline.

Coverage goes down because more lines were added :/

Author: beefancohen

package.json

@@ -20,7 +20,7 @@
     "build": "rimraf lib && babel src --out-dir lib",
     "prepublish": "npm run lint && npm run test && npm run build",
     "coveralls": "cat ./reports/coverage/lcov.info | coveralls",
-    "lint": "eslint  --config .eslintrc.js src tests",
+    "lint": "eslint  --config .eslintrc.js src/**/*.js tests/**/*.js",
     "pretest": "npm run lint",
     "test": "istanbul cover --dir reports/coverage node_modules/mocha/bin/_mocha tests/**/*.js -- --compilers js:babel-core/register --reporter dot"
   },

src/index.js

@@ -24,19 +24,19 @@ module.exports = {
         }
       },
       rules: {
-        "jsx-a11y/img-uses-alt": 2,
-        "jsx-a11y/redundant-alt": 2,
-        "jsx-a11y/onclick-uses-role": 2,
-        "jsx-a11y/mouse-events-map-to-key-events": 2,
-        "jsx-a11y/use-onblur-not-onchange": 2,
-        "jsx-a11y/no-access-key": 2,
-        "jsx-a11y/label-uses-for": 2,
-        "jsx-a11y/no-hash-href": 2,
-        "jsx-a11y/valid-aria-role": 2,
-        "jsx-a11y/valid-aria-proptypes": 2,
-        "jsx-a11y/no-invalid-aria": 2,
-        "jsx-a11y/role-requires-aria": 2,
-        "jsx-a11y/no-unsupported-elements-use-aria": 2
+        'jsx-a11y/img-uses-alt': 2,
+        'jsx-a11y/redundant-alt': 2,
+        'jsx-a11y/onclick-uses-role': 2,
+        'jsx-a11y/mouse-events-map-to-key-events': 2,
+        'jsx-a11y/use-onblur-not-onchange': 2,
+        'jsx-a11y/no-access-key': 2,
+        'jsx-a11y/label-uses-for': 2,
+        'jsx-a11y/no-hash-href': 2,
+        'jsx-a11y/valid-aria-role': 2,
+        'jsx-a11y/valid-aria-proptypes': 2,
+        'jsx-a11y/no-invalid-aria': 2,
+        'jsx-a11y/role-requires-aria': 2,
+        'jsx-a11y/no-unsupported-elements-use-aria': 2
       }
     }
   }

src/util/getAttributeValue.js

@@ -1,8 +1,13 @@
 'use strict';
 
-import { getValue, getLiteralValue } from './values';
+import {
+  default as getValue,
+  getLiteralValue
+} from './values';
 
-const extract = (attribute, extractor) => {
+
+
+const extractValue = (attribute, extractor) => {
   if (attribute.type === 'JSXAttribute') {
     if (attribute.value === null) {
       // Null valued attributes imply truthiness.
@@ -27,8 +32,22 @@ const extract = (attribute, extractor) => {
  *
  * @param attribute - The JSXAttribute collected by AST parser.
  */
-const getAttributeValue = attribute => extract(attribute, getValue);
+export default function getAttributeValue(attribute) {
+  return extractValue(attribute, getValue);
+}
 
-export const getLiteralAttributeValue = attribute => extract(attribute, getLiteralValue);
+/**
+ * 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 a value only if we can extract
+ * a literal value from its attribute (i.e. values that have generic
+ * types in JavaScript - strings, numbers, booleans, etc.)
+ *
+ * @param attribute - The JSXAttribute collected by AST parser.
+ */
+export const getLiteralAttributeValue = function getLiteralAttributeValue(attribute) {
+  return extractValue(attribute, getLiteralValue);
+};
 
-export default getAttributeValue;

src/util/getNodeType.js

@@ -1,6 +1,9 @@
 'use strict';
 
-const getNodeType = node => {
+/**
+ * Returns the tagName associated with a JSXElement.
+ */
+export default function getNodeType(node) {
   const { name } = node;
 
   if (name.type === 'JSXMemberExpression') {
@@ -9,7 +12,5 @@ const getNodeType = node => {
   }
 
   return node.name.name;
-};
-
-export default getNodeType;
+}
 

src/util/hasAttribute.js

@@ -1,6 +1,5 @@
 'use strict';
 
-
 /**
  * Returns the JSXAttribute itself or false, indicating the attribute
  * is not present on the JSXOpeningElement. This skips over spread attributes

src/util/isHiddenFromScreenReader.js

@@ -3,6 +3,8 @@
 import hasAttribute from './hasAttribute';
 import getAttributeValue from './getAttributeValue';
 
+
+
 /**
  * Returns boolean indicating that the aria-hidden prop
  * is present or the value is true.
@@ -11,7 +13,7 @@ import getAttributeValue from './getAttributeValue';
  */
 const isHiddenFromScreenReader = attributes => {
   const ariaHidden = getAttributeValue(hasAttribute(attributes, 'aria-hidden'));
-  return ariaHidden === true || ariaHidden === null;
+  return ariaHidden === true;
 };
 
 export default isHiddenFromScreenReader;

src/util/isInteractiveElement.js

@@ -4,6 +4,9 @@ import hasAttribute from './hasAttribute';
 import getAttributeValue from './getAttributeValue';
 import DOMElements from './attributes/DOM';
 
+
+
+// Map of tagNames to functions that return whether that element is interactive or not.
 const interactiveMap = {
   a: attributes => {
     const hasHref = hasAttribute(attributes, 'href');

src/util/values/JSXElement.js

@@ -1,3 +1,11 @@
-const extract = () => undefined;
+'use strict';
 
-export default extract;
+/**
+ * Extractor function for a JSXElement type value node.
+ *
+ * Currently just returns undefined as we haven't found
+ * a use case for this yet.
+ */
+export default function extractValueFromJSXElement() {
+  return undefined;
+}

src/util/values/Literal.js

@@ -1,4 +1,12 @@
-const extract = value => {
+'use strict';
+
+/**
+ * Extractor function for a Literal type value node.
+ *
+ * @param - value - AST Value object with type `Literal`
+ * @returns { String|Boolean } - The extracted value converted to correct type.
+ */
+export default function extractValueFromLiteral(value) {
   const { value: extractedValue } = value;
 
   if (extractedValue === 'true') {
@@ -8,6 +16,4 @@ const extract = value => {
   }
 
   return extractedValue;
-};
-
-export default extract;
+}

src/util/values/expressions/CallExpression.js

@@ -1,5 +1,18 @@
+'use strict';
+
 import getValue from './index';
 
-const extract = value => getValue(value.callee);
 
-export default extract;
+
+/**
+ * Extractor function for a CallExpression type value node.
+ * A call expression looks like `bar()`
+ * This will return `bar` as the value to indicate its existence,
+ * since we can not execute the function bar in a static environment.
+ *
+ * @param - value - AST Value object with type `CallExpression`
+ * @returns - The extracted value converted to correct type.
+ */
+export default function extractValueFromCallExpression(value) {
+  return getValue(value.callee);
+}