Add support for wildcards to u.updateIn

Fixes #27

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Change Log
 
 ## [unreleased]
+* Add support for wildcards (`*`) to `u.updateIn`. (https://github.com/substantial/updeep/issues/27)
 
 ## [0.9.0]
 * Do not add object during false branch of `u.if`.

README.md

@@ -186,7 +186,7 @@ expect(result).to.eql({ name: "Joe Merrill", age: 22 });
 
 ### `u.updateIn(path(, value)(, object))`
 
-Update a single value with a simple string or array path. Can be use to update nested objects, arrays, or a combination.
+Update a single value with a simple string or array path. Can be use to update nested objects, arrays, or a combination. Can also be used to update every element of a nested array with `'*'`.
 
 ```js
 var result = u.updateIn('bunny.color', 'brown', { bunny: { color: 'black' } });
@@ -214,6 +214,22 @@ var result = u({ pets: u.updateIn([0, 'bunny', 'age'], 3) }, { pets: [{ bunny: {
 expect(result).to.eql({ pets: [{ bunny: { age: 3 } }] });
 ```
 
+```js
+var result = u.updateIn('todos.*.done', true, {
+  todos: [
+    { done: false },
+    { done: false },
+  ]
+});
+
+expect(result).to.eql({
+  todos: [
+    { done: true },
+    { done: true },
+  ]
+});
+```
+
 ### `u.constant(object)`
 
 Sometimes, you want to replace an object outright rather than merging it.

lib/updateIn.js

@@ -1,10 +1,26 @@
 import curry from './util/curry';
 import update from './update';
+import map from './map';
 import splitPath from './util/splitPath';
 
+const wildcard = '*';
+
+function reducePath(acc, key) {
+  if (key === wildcard) {
+    return value =>
+      Object.prototype.hasOwnProperty.call(value, wildcard) ?
+        // If we actually have wildcard as a property, update that
+        update({ [wildcard]: acc }, value) :
+        // Otherwise map over all properties
+        map(acc, value);
+  }
+
+  return { [key]: acc };
+}
+
 function updateIn(path, value, object) {
   const parts = splitPath(path);
-  const updates = parts.reduceRight((acc, key) => ({ [key]: acc }), value);
+  const updates = parts.reduceRight(reducePath, value);
 
   return update(updates, object);
 }

test/updateIn-spec.js

@@ -48,4 +48,20 @@ describe('u.updateIn', () => {
   it('freezes the result', () => {
     expect(Object.isFrozen(u.updateIn('a', 0, {}))).to.be.true;
   });
+
+  it('can multiple elements of an array with *', () => {
+    let object = { a: [{ b: 0 }, { b: 1 }, { b: 2 }] };
+    let result = u.updateIn('a.*.b', x => x + 1, object);
+    expect(result).to.eql({ a: [{ b: 1 }, { b: 2 }, { b: 3 }] });
+
+    object = { a: [0, 1, 2] };
+    result = u.updateIn(['a', '*'], x => x + 1, object);
+    expect(result).to.eql({ a: [1, 2, 3] });
+  });
+
+  it('can update properties named *', () => {
+    const object = { '*': 1, x: 1 };
+    const result = u.updateIn('*', x => x + 1, object);
+    expect(result).to.eql({ '*': 2, x: 1 });
+  });
 });