Created
May 16, 2023 17:41
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| export const DELETE = Symbol('DELETE'); | |
| /** | |
| * Traverse an object and apply a transformation function to each value. | |
| * The transformation function is called with the value, the key and the key path. | |
| * | |
| * The transformation function can return a new value or the same value. | |
| * If the transformation function returns a new value, the value in the object is replaced with the new value. | |
| * | |
| * The transformation function can return an object. | |
| * If the transformation function returns an object, the object is traversed as well. | |
| * | |
| * Warning: The transformation could loop infinitely if it always returns an object. | |
| * | |
| * @param obj { object } - the object to traverse | |
| * @param transform { (value: unknown, key: string, keyPath: string) => unknown } - a function that transforms the value, the key and the key path | |
| */ | |
| export async function traverse(obj, transform) { | |
| /** | |
| * @type { object[] } | |
| */ | |
| const objectStack = [obj]; | |
| /** | |
| * @type { string[] } | |
| */ | |
| const keysStack = [] | |
| while (objectStack.length > 0) { | |
| const obj = objectStack.pop(); | |
| if (obj) { | |
| for (const key in obj) { | |
| keysStack.push(key); | |
| const keyPath = keysStack.join('.'); | |
| const value = obj[key]; | |
| const transformed = transform(value, key, keyPath); | |
| if (transformed === DELETE) { | |
| delete obj[key]; | |
| keysStack.pop(); | |
| continue; | |
| } | |
| if (transformed !== value) { | |
| obj[key] = transformed; | |
| } | |
| if (typeof transformed === 'object' && transformed !== null) { | |
| objectStack.push(transformed); | |
| } else { | |
| keysStack.pop(); | |
| } | |
| } | |
| } | |
| } | |
| } | |
| /** | |
| * Traverse an object and apply a transformation function to each value. | |
| * The transformation function is called with the value, the key and the key path. | |
| * | |
| * The transformation function can return a new value or the same value. | |
| * If the transformation function returns a new value, the value in the object is replaced with the new value. | |
| * | |
| * The transformation function can return an object. | |
| * If the transformation function returns an object, the object is traversed as well. | |
| * | |
| * The transformation function can return a promise. | |
| * If the transformation function returns a promise, the promise is awaited and the resolved value is used. | |
| * | |
| * Warning: The transformation could loop infinitely if it always returns an object. | |
| * | |
| * @param obj { object } - the object to traverse | |
| * @param transform { (value: unknown, key: string, keyPath: string) => unknown | Promise<unknown> } - a function that transforms the value, the key and the key path | |
| * @returns | |
| **/ | |
| export async function traverseAsync(obj, transform) { | |
| /** | |
| * @type { object[] } | |
| */ | |
| const objectStack = [obj]; | |
| /** | |
| * @type { string[] } | |
| */ | |
| const keysStack = [] | |
| while (objectStack.length > 0) { | |
| const obj = objectStack.pop(); | |
| if (obj) { | |
| for (const key in obj) { | |
| keysStack.push(key); | |
| const keyPath = keysStack.join('.'); | |
| const value = obj[key]; | |
| const awaitedValue = await value; | |
| const transformed = await transform(awaitedValue, key, keyPath); | |
| if (transformed === DELETE) { | |
| delete obj[key]; | |
| keysStack.pop(); | |
| continue; | |
| } | |
| if (value !== transformed) { | |
| obj[key] = transformed; | |
| } | |
| if (typeof transformed === 'object' && transformed !== null) { | |
| objectStack.push(transformed); | |
| } else { | |
| keysStack.pop(); | |
| } | |
| } | |
| } | |
| } | |
| } | |
| const obj = { a: 1, b: { c: [{ a: 2 }, { d: 20 }] } } | |
| traverse(obj, (value, key, keyPath) => { | |
| if (keyPath === 'a') { | |
| return DELETE; | |
| } | |
| return value | |
| }) | |
| obj | |
| const asyncObj = { a: 1, b: { c: Promise.resolve([{ a: 2 }]) } } | |
| traverseAsync(asyncObj, (value, key, keyPath) => { | |
| if (keyPath === 'a') { | |
| return DELETE; | |
| } | |
| return value | |
| }).then(() => { | |
| asyncObj | |
| }) |
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