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Flatten Json


This act extracts all arrays from input JSON and extends their elements with the core object.

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Author's avatarPetr Cermak
  • Modified
  • Users20
  • Runs485


# First, specify the base Docker image. You can read more about
# the available images at
# You can also use any other image from Docker Hub.
FROM apify/actor-node:16

# Second, copy just package.json and package-lock.json since those are the only
# files that affect "npm install" in the next step, to speed up the build.
COPY package*.json ./

# Install NPM packages, skip optional and development dependencies to
# keep the image small. Avoid logging too much and print the dependency
# tree for debugging
RUN npm --quiet set progress=false \
 && npm install --only=prod --no-optional \
 && echo "Installed NPM packages:" \
 && (npm list || true) \
 && echo "Node.js version:" \
 && node --version \
 && echo "NPM version:" \
 && npm --version

# Next, copy the remaining files and directories with the source code.
# Since we do this after NPM install, quick build will be really fast
# for most source file changes.
COPY . ./

# Optionally, specify how to launch the source code of your actor.
# By default, Apify's base Docker images define the CMD instruction
# that runs the Node.js source code using the command specified
# in the "scripts.start" section of the package.json file.
# In short, the instruction looks something like this:
# CMD npm start

# My beautiful actor

Contains a documentation what your actor does and how to use it,
which is then displayed in the app or library. It's always a good
idea to write a good, in a few months not even you
will remember all the details about the actor.

You can use [Markdown](
language for rich formatting.


const Apify = require('apify');

function extractArrays(obj){
    const arrays = {};
    for(let key in obj){
        const val = obj[key];
            arrays[key] = val;
            delete obj[key];
    return arrays;

function extendArray(array, name, extObj){
    const result = [];
    for(let elem of array){
        result.push(({[name]: elem,... extObj }));
    return result;

function getExtended(obj){
    let results = [];
    const arrays = extractArrays(obj);
    for(let key in arrays){
        results = results.concat(extendArray(arrays[key], key, obj));
    return results;

Apify.main(async () => {
    const input = await Apify.getValue('INPUT');

    let output = [];
    for(let inObj of input){
        output = output.concat(getExtended(inObj));
    await Apify.setValue('OUTPUT', output);


    "name": "my-actor",
    "version": "0.0.1",
    "dependencies": {
        "apify": "^2.2.2"
    "scripts": {
        "start": "node main.js"
    "author": "Me!"