如何在 JS 中循环遍历复杂的 object

Question

This is my obj, I just want to loop through this and show the errors:

var obj = {
    "error": {
        "errors": {
            "username": {
                "properties": {
                    "message": "username field is empty.",
                    "type": "required",
                    "path": "username"
                },
                "kind": "required",
                "path": "username"
            },
            "email": {
                "properties": {
                    "message": "email field is empty.",
                    "type": "required",
                    "path": "email"
                },
                "kind": "required",
                "path": "email"
            },
            "password": {
                "properties": {
                    "message": "password field is empty.",
                    "type": "required",
                    "path": "password"
                },
                "kind": "required",
                "path": "password"
            }
        },
        "_message": "User validation failed",
        "message": "User validation failed: username: username field is empty., email: email field is empty., password: password field is empty."
    }
}

I want to show the errors: properties.message but I'm having hard time, this is what I tried so far:

for (var key in obj.error.errors) {
    for (var key2 in key.properties){
        for (var key3 in key2.message){
            console.log(key3)
        } 
    } 
}

But the console is blank.

Answer 1

In the loop you are getting the key, not the object itself. Also you don't need to add all those loops if your data is structured like that. Just pick the errors, iterate through all.

for(var d in obj.error.errors){
    console.log(a[d].properties.message)
}

Answer 2

a working solution

Object.values(obj.error.errors).forEach((error) => { console.log(error.properties.message) })

Looking to your data structure, you only need to iterate on the 'errors' list

Answer 3

Check this out, it will return you in the properties:message format

 const obj = { "error": { "errors": { "username": { "properties": { "message": "username field is empty.", "type": "required", "path": "username" }, "kind": "required", "path": "username" }, "email": { "properties": { "message": "email field is empty.", "type": "required", "path": "email" }, "kind": "required", "path": "email" }, "password": { "properties": { "message": "password field is empty.", "type": "required", "path": "password" }, "kind": "required", "path": "password" } }, "_message": "User validation failed", "message": "User validation failed: username: username field is empty., email: email field is empty., password: password field is empty." } }; const objVal = Object.values(obj.error.errors); const errors = objVal.reduce((obj, item) => { return (obj[item.path] = item.properties.message, obj) },{}) console.log(errors);