const data = {
"desk": {
"drawer": "stapler"
},
"cabinet": {
"top drawer": {
"folder1": "a file",
"folder2": "secrets"
},
"bottom drawer": "soda"
},
"item" : [
{
"hello" : {
"world" : "isHere"
},
"test" : "1"
},
{
"hello" : {
"world" : "isHere2"
},
"test" : "2"
},
]
};
const iterate = (obj) => {
Object.keys(obj).forEach(key => {
if (typeof obj[key] === 'object') {
iterate(obj[key])
} else{
let value = obj[key];
let newObj = {[key]: value, 'style' : {backGroundColor : 'red'}};
delete obj[key];
Object.assign(obj, newObj);
}
})
}
iterate(data);
console.log(data)I have wrote a recursive function that should replace each key-value pair (not property!) with a object that i specify in the parameter.
However, if I use a array.forEach loop inside the function, the passed obj is undefined.
What am I missing?
Example
const iterate = (obj, newObj) => {
Object.keys(obj).forEach(key => {
if (typeof obj[key] === 'object') {
iterate(obj[key])
} else{
delete obj[key];
Object.assign(obj, newObj);
}
})
}
However, if I define the object within the forEach, it works perfectly ....
const iterate = (obj) => {
Object.keys(obj).forEach(key => {
if (typeof obj[key] === 'object') {
iterate(obj[key])
} else{
let value = obj[key];
// SEE HERE
let newObj = {[key]: value, 'style' : {backGroundColor : 'red'}};
delete obj[key];
Object.assign(obj, newObj);
}
})
}
Why does the Object.keys(obj).forEach not see the passed parameter in the first version? And what is the solution?
You need to pass newObj whenever you call iterate inside the Array.forEach() - iterate(obj[key], newObj):
const data = {"desk":{"drawer":"stapler"},"cabinet":{"top drawer":{"folder1":"a file","folder2":"secrets"},"bottom drawer":"soda"},"item":[{"hello":{"world":"isHere"},"test":"1"},{"hello":{"world":"isHere2"},"test":"2"}]};
const iterate = (obj, newObj) => {
Object.keys(obj).forEach(key => {
if (typeof obj[key] === 'object') {
iterate(obj[key], newObj)
} else {
// delete obj[key]; // remove for example purposes
Object.assign(obj, newObj);
}
})
}
const newObj = {
'style': {
backGroundColor: 'red'
}
};
iterate(data, newObj);
console.log(data)