feat(new-tool): diff of two json objects

src/tools/json-diff/json-diff.models.ts

@@ -0,0 +1,140 @@
+import _ from 'lodash';
+import type { Difference, DifferenceStatus } from './json-diff.types';
+
+export { diff };
+
+function diff(
+  obj: unknown,
+  newObj: unknown,
+  { onlyShowDifferences = false }: { onlyShowDifferences?: boolean } = {},
+): Difference {
+  if (_.isArray(obj) && _.isArray(newObj)) {
+    return {
+      key: '',
+      type: 'array',
+      children: diffArrays(obj, newObj, { onlyShowDifferences }),
+      oldValue: obj,
+      value: newObj,
+      status: getStatus(obj, newObj),
+    };
+  }
+
+  if (_.isObject(obj) && _.isObject(newObj)) {
+    return {
+      key: '',
+      type: 'object',
+      children: diffObjects(obj as Record<string, unknown>, newObj as Record<string, unknown>, { onlyShowDifferences }),
+      oldValue: obj,
+      value: newObj,
+      status: getStatus(obj, newObj),
+    };
+  }
+
+  return {
+    key: '',
+    type: 'value',
+    oldValue: obj,
+    value: newObj,
+    status: getStatus(obj, newObj),
+  };
+}
+
+function diffObjects(
+  obj: Record<string, unknown>,
+  newObj: Record<string, unknown>,
+  { onlyShowDifferences = false }: { onlyShowDifferences?: boolean } = {},
+): Difference[] {
+  const keys = Object.keys({ ...obj, ...newObj });
+  return keys
+    .map((key) => createDifference(obj?.[key], newObj?.[key], key, { onlyShowDifferences }))
+    .filter((diff) => !onlyShowDifferences || diff.status !== 'unchanged');
+}
+
+function createDifference(
+  value: unknown,
+  newValue: unknown,
+  key: string | number,
+  { onlyShowDifferences = false }: { onlyShowDifferences?: boolean } = {},
+): Difference {
+  const type = getType(value);
+
+  if (type === 'object') {
+    return {
+      key,
+      type,
+      children: diffObjects(value as Record<string, unknown>, newValue as Record<string, unknown>, {
+        onlyShowDifferences,
+      }),
+      oldValue: value,
+      value: newValue,
+      status: getStatus(value, newValue),
+    };
+  }
+
+  if (type === 'array') {
+    return {
+      key,
+      type,
+      children: diffArrays(value as unknown[], newValue as unknown[], { onlyShowDifferences }),
+      value: newValue,
+      oldValue: value,
+      status: getStatus(value, newValue),
+    };
+  }
+
+  return {
+    key,
+    type,
+    value: newValue,
+    oldValue: value,
+    status: getStatus(value, newValue),
+  };
+}
+
+function diffArrays(
+  arr: unknown[],
+  newArr: unknown[],
+  { onlyShowDifferences = false }: { onlyShowDifferences?: boolean } = {},
+): Difference[] {
+  const maxLength = Math.max(0, arr?.length, newArr?.length);
+  return Array.from({ length: maxLength }, (_, i) =>
+    createDifference(arr?.[i], newArr?.[i], i, { onlyShowDifferences }),
+  ).filter((diff) => !onlyShowDifferences || diff.status !== 'unchanged');
+}
+
+function getType(value: unknown): 'object' | 'array' | 'value' {
+  if (value === null) {
+    return 'value';
+  }
+  if (Array.isArray(value)) {
+    return 'array';
+  }
+  if (typeof value === 'object') {
+    return 'object';
+  }
+  return 'value';
+}
+
+function getStatus(value: unknown, newValue: unknown): DifferenceStatus {
+  if (value === undefined) {
+    return 'added';
+  }
+
+  if (newValue === undefined) {
+    return 'removed';
+  }
+
+  const bothAreObjects = getType(value) === 'object' && getType(newValue) === 'object';
+  const bothAreArrays = getType(value) === 'array' && getType(newValue) === 'array';
+  const bothAreDeepEqual = _.isEqual(value, newValue);
+
+  if (bothAreDeepEqual) {
+    return 'unchanged';
+  }
+
+  if (bothAreObjects || bothAreArrays) {
+    return 'children-updated';
+  }
+
+  return 'updated';
+}