Add setIn helper

Author: WezomDev

src/set-in.test.ts

@@ -0,0 +1,115 @@
+// -----------------------------------------------------------------------------
+// Deps
+// -----------------------------------------------------------------------------
+
+import { setIn } from './set-in';
+import { IPlainObject } from './types';
+
+// -----------------------------------------------------------------------------
+// Tests
+// -----------------------------------------------------------------------------
+
+const testCases: {
+	parameters: Parameters<typeof setIn>;
+	result: IPlainObject;
+}[] = [
+	{
+		parameters: [{}, 'key', 'value'],
+		result: { key: 'value' }
+	},
+	{
+		parameters: [{}, 'key1.key2.key3.key4', 'value'],
+		result: {
+			key1: {
+				key2: {
+					key3: {
+						key4: 'value'
+					}
+				}
+			}
+		}
+	},
+	{
+		parameters: [
+			{
+				key1: {
+					key2: {
+						xxx: true,
+						zzz: false
+					}
+				}
+			},
+			'key1.key2.key3.key4',
+			'value'
+		],
+		result: {
+			key1: {
+				key2: {
+					xxx: true,
+					zzz: false,
+					key3: {
+						key4: 'value'
+					}
+				}
+			}
+		}
+	},
+	{
+		parameters: [{ list: [] }, 'list[2]', 'value'],
+		result: {
+			list: [undefined, undefined, 'value']
+		}
+	},
+	{
+		parameters: [{}, 'list[2]', 'value'],
+		result: {
+			list: [undefined, undefined, 'value']
+		}
+	},
+	{
+		parameters: [{}, 'key1[0].key3', 'value'],
+		result: {
+			key1: [
+				{
+					key3: 'value'
+				}
+			]
+		}
+	}
+];
+
+describe('setIn tool', () => {
+	testCases.forEach(({ parameters, result }, i) => {
+		test(`test #${i + 1}: ${parameters.join(', ')}`, () => {
+			if (typeof result === 'string') {
+			} else {
+				setIn(...parameters);
+				const _expect = JSON.stringify(parameters[0], undefined, '\t');
+				const _result = JSON.stringify(result, undefined, '\t');
+				expect(_expect).toStrictEqual(_result);
+			}
+		});
+	});
+});
+
+// -----------------------------------------------------------------------------
+// Error handling
+// -----------------------------------------------------------------------------
+
+const errorCases: {
+	parameters: Parameters<typeof setIn>;
+	error: string | RegExp;
+}[] = [
+	{
+		parameters: [{ list: [] }, 'list.item', 'value'],
+		error: /must be an array index \(correct int\)/
+	}
+];
+
+describe('setIn tool: error handling', () => {
+	errorCases.forEach(({ parameters, error }, i) => {
+		test(`error #${i + 1}: ${error}`, () => {
+			expect(() => setIn(...parameters)).toThrow(error);
+		});
+	});
+});

src/set-in.ts

@@ -0,0 +1,70 @@
+// -----------------------------------------------------------------------------
+// Deps
+// -----------------------------------------------------------------------------
+
+import { toPath } from './to-path';
+import { isPlainObject } from './is-plain-object';
+import { IPlainObject } from './types';
+
+// -----------------------------------------------------------------------------
+// Helper
+// -----------------------------------------------------------------------------
+
+const setInRecursive = (
+	current: any | any[],
+	value: any,
+	path: (string | number)[],
+	index: number
+) => {
+	if (index >= path.length) {
+		return;
+	}
+	const key = path[index];
+	const nextIndex = index + 1;
+	const numberKey = typeof key === 'number';
+	const sampleIsArray = Array.isArray(current);
+
+	if (nextIndex === path.length) {
+		if (sampleIsArray) {
+			if (numberKey) {
+				current[key] = value;
+			} else {
+				throw new Error(`Key \`${key}\` must be an array index (correct int)`);
+			}
+		} else if (isPlainObject(current)) {
+			current[key] = value;
+		} else {
+			throw new Error('Last chain must be an object or array');
+		}
+	} else {
+		if (isPlainObject(current)) {
+			if (!current.hasOwnProperty(key)) {
+				// setting inner prop based on next path index
+				current[key] = typeof path[nextIndex] === 'number' ? [] : {};
+			}
+			setInRecursive(current[key], value, path, nextIndex);
+		} else {
+			throw new Error('`setIn()` tool ends up with wrong result');
+		}
+	}
+};
+
+/**
+ * Setting value in Object by path
+ * Inspired by final-form's `setIn` helper
+ * {@link https://github.com/final-form/final-form/blob/master/src/structure/setIn.js}
+ * @param {IPlainObject} sample
+ * @param {string} keyPath
+ * @param {*} value
+ */
+export function setIn(sample: IPlainObject, keyPath: string, value: any) {
+	return setInRecursive(
+		sample,
+		value,
+		toPath(keyPath).map((key) => {
+			const index = parseInt(key);
+			return isNaN(index) ? key : index;
+		}),
+		0
+	);
+}