Merge pull request #106 from ajthinking/nested-merge

Nested merge

packages/core/src/computers/ReplaceItem/ReplaceItem.test.ts

@@ -26,17 +26,33 @@ it('merges items when mode is set to MERGE', () => {
     .hasParams({
       mode: 'MERGE',
       json: `{
-        newKey: newValue
+        properties: {
+          newProp: newPropValue
+        }
       }`
     })
     .getsInput([
       {},
-      { existingKey: 'existingValue' }
+      {
+        id: 1,
+        properties: {
+          existingProp: 'existingPropValue'
+        }
+      }
     ])
     .doRun()
     .expectOutput([
-      { newKey: 'newValue' },
-      { existingKey: 'existingValue', newKey: 'newValue' },
+      {
+        properties: {
+          newProp: 'newPropValue',
+        }
+      },      
+      {
+        properties: {
+          existingProp: 'existingPropValue',
+          newProp: 'newPropValue',
+        }
+      },
     ])
     .ok()
 })

packages/core/src/computers/ReplaceItem/ReplaceItem.ts

@@ -2,6 +2,7 @@
 import { JsEvaluation, JsonEvaluation, HjsonEvaluation, json_ } from '../../Param';
 import { ComputerConfig } from '../../types/ComputerConfig';
 import { ItemValue } from '../../types/ItemValue';
+import { merge } from '../../utils/merge';
 import { multiline } from '../../utils/multiline';
 
 export const ReplaceItem: ComputerConfig = {
@@ -45,10 +46,7 @@ export const ReplaceItem: ComputerConfig = {
       const replacers = incoming.map(item => {
         if(params.mode === 'REPLACE') return item.params.json as ItemValue;
 
-        if(params.mode === 'MERGE')return {
-          ...item.value,
-          ...item.params.json as Object,
-        }
+        if(params.mode === 'MERGE') return merge(item.value, item.params.json as Object);
 
         throw new Error(`Unknown mode: ${params.mode}`)
       })

packages/core/src/utils/merge.test.ts

@@ -0,0 +1,15 @@
+import { merge } from './merge';
+
+it('merges flat objects', () => {
+  const first = { a: 1 };
+  const second = { a: 2, b: 3 };
+
+  expect(merge(first, second)).toEqual({ a: 2, b: 3 });
+});
+
+it('merges nested objects', () => {
+  const first = { a: { b: 1, c: 2 } };
+  const second = { a: { b: 'new' } };
+
+  expect(merge(first, second)).toEqual({ a: { b: 'new', c: 2 } });
+});

packages/core/src/utils/merge.ts

@@ -0,0 +1,14 @@
+type Obj = {
+  [key: string]: any
+}
+
+export const merge = (first: Obj, second: Obj) => {
+  // Iterate through `source` properties and if an `Object` set property to merge of `target` and `source` properties
+  for (const key of Object.keys(second)) {
+    if (second[key] instanceof Object)
+      Object.assign(second[key], merge(first[key], second[key]));
+  }
+  // Join `target` and modified `source`
+  Object.assign(first || {}, second);
+  return first;
+}

packages/core/src/utils/multiline.test.ts

@@ -0,0 +1,24 @@
+import { multiline } from './multiline';
+
+
+it('removes first line when it is empty', () => {
+  const result = multiline`
+    content
+  `;
+
+  expect(result).toEqual('content\n');
+});
+
+it('bases indentation on the first content line', () => {
+  const result = multiline`
+    heading
+      p1
+      p2
+  `;
+
+  expect(result).toEqual('heading\n  p1\n  p2\n');
+});
+
+it('throws if it gets content on first line', () => {
+  expect(() => multiline`content-on-first-line`).toThrow();
+});

packages/core/src/utils/multiline.ts

@@ -7,11 +7,14 @@ export const multiline = (strings: TemplateStringsArray, ...values: any[]) => {
   // Split the string into lines
   let lines = combinedString.split('\n');
 
-  // Remove the first line if it is empty
-  if (lines[0].trim() === '') {
-    lines = lines.slice(1);
+  // Throw if the first line is not empty
+  if (lines[0].trim() !== '') {
+    throw new Error(`First line of multiline string must be empty. The content was ${combinedString}`);
   }
 
+  // Remove the first line
+  lines = lines.slice(1);
+
   // Find the minimum indentation of all lines (except empty lines)
   const baseIndentation = Math.min(...lines.filter(line => line.trim() !== '').map(line => line.search(/\S|$/)));