refactor: Extract etwp helper functions

Author: joshwiens

.eslintrc

@@ -1,3 +1,10 @@
 {
-  "extends": "webpack"
-}
+  "extends": "webpack",
+  "rules": {
+    "prefer-destructuring": 1,
+    "prefer-rest-params": 1,
+    "no-plusplus": 1,
+    "consistent-return": 1,
+    "no-param-reassign": 1
+  }
+}

src/lib/helpers.js

@@ -0,0 +1,56 @@
+export function isInitialOrHasNoParents(chunk) {
+  return chunk.isInitial() || chunk.parents.length === 0;
+}
+
+export function isInvalidOrder(a, b) {
+  const bBeforeA = a.getPrevModules().includes(b);
+  const aBeforeB = b.getPrevModules().includes(a);
+  return aBeforeB && bBeforeA;
+}
+
+export function getOrder(a, b) {
+  const aOrder = a.getOrder();
+  const bOrder = b.getOrder();
+  if (aOrder < bOrder) return -1;
+  if (aOrder > bOrder) return 1;
+  const aIndex = a.getOriginalModule().index2;
+  const bIndex = b.getOriginalModule().index2;
+  if (aIndex < bIndex) return -1;
+  if (aIndex > bIndex) return 1;
+  const bBeforeA = a.getPrevModules().includes(b);
+  const aBeforeB = b.getPrevModules().includes(a);
+  if (aBeforeB && !bBeforeA) return -1;
+  if (!aBeforeB && bBeforeA) return 1;
+  const ai = a.identifier();
+  const bi = b.identifier();
+  if (ai < bi) return -1;
+  if (ai > bi) return 1;
+  return 0;
+}
+
+export function getLoaderObject(loader) {
+  if (isString(loader)) {
+    return { loader };
+  }
+  return loader;
+}
+
+export function mergeOptions(a, b) {
+  if (!b) return a;
+  Object.keys(b).forEach((key) => {
+    a[key] = b[key];
+  });
+  return a;
+}
+
+export function isString(a) {
+  return typeof a === 'string';
+}
+
+export function isFunction(a) {
+  return isType('Function', a);
+}
+
+export function isType(type, obj) {
+  return Object.prototype.toString.call(obj) === `[object ${type}]`;
+}