I have this JSON from Mongoose error catching on a NodeJS app with the express framework:
{
"err": {
"errors": {
"last_name": {
"message": "Path `last_name` is required.",
"name": "ValidatorError",
"properties": {
"message": "Path `last_name` is required.",
"type": "required",
"path": "last_name"
},
"kind": "required",
"path": "last_name"
},
"first_name": {
"message": "Path `first_name` is required.",
"name": "ValidatorError",
"properties": {
"message": "Path `first_name` is required.",
"type": "required",
"path": "first_name"
},
"kind": "required",
"path": "first_name"
},
"password": {
"message": "Path `password` (`iam`) is shorter than the minimum allowed length (6).",
"name": "ValidatorError",
"properties": {
"message": "Path `password` (`iam`) is shorter than the minimum allowed length (6).",
"type": "minlength",
"minlength": 6,
"path": "password",
"value": "iam"
},
"kind": "minlength",
"path": "password",
"value": "iam"
}
},
"_message": "User validation failed",
"message": "User validation failed: last_name: Path `last_name` is required., first_name: Path `first_name` is required., password: Path `password` (`iam`) is shorter than the minimum allowed length (6).",
"name": "ValidationError"
}
}
How can I get the type and path of each error inside the properties, I have tried forEach() method but it didn't work, is there any other way to loop through this JSON?
Shidersz
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asked May 19, 2019 at 18:04
Kadiem Alqazzaz
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You can browse with Object.keys().Antoine Olivier– Antoine Olivier2019年05月19日 18:12:00 +00:00Commented May 19, 2019 at 18:12
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Possible duplicate of How do I loop through or enumerate a JavaScript object?kgrg– kgrg2019年05月19日 19:38:48 +00:00Commented May 19, 2019 at 19:38
2 Answers 2
Find the keys, the iterate over the keys. Add those results to some data structure.
I've chose to use map on the keys and added to an array.
const errors = {
"err": {
"errors": {
"last_name": {
"message": "Path `last_name` is required.",
"name": "ValidatorError",
"properties": {
"message": "Path `last_name` is required.",
"type": "required",
"path": "last_name"
},
"kind": "required",
"path": "last_name"
},
"first_name": {
"message": "Path `first_name` is required.",
"name": "ValidatorError",
"properties": {
"message": "Path `first_name` is required.",
"type": "required",
"path": "first_name"
},
"kind": "required",
"path": "first_name"
},
"password": {
"message": "Path `password` (`iam`) is shorter than the minimum allowed length (6).",
"name": "ValidatorError",
"properties": {
"message": "Path `password` (`iam`) is shorter than the minimum allowed length (6).",
"type": "minlength",
"minlength": 6,
"path": "password",
"value": "iam"
},
"kind": "minlength",
"path": "password",
"value": "iam"
}
},
"_message": "User validation failed",
"message": "User validation failed: last_name: Path `last_name` is required., first_name: Path `first_name` is required., password: Path `password` (`iam`) is shorter than the minimum allowed length (6).",
"name": "ValidationError"
}
}
let output = Object.keys(errors.err.errors).map(key => { return {type:errors.err.errors[key].properties.type, path:errors.err.errors[key].properties.path} });
console.log(output);
answered May 19, 2019 at 18:12
Randy Casburn
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2 Comments
some
map returns an array. You do not need to first create output =[] and then pushing in the function. Just do let output=Object.keys(errors.err.errors).map(key =>({type:errors.err.errors[key].properties.type, path:errors.err.errors[key].properties.path})). If you don't want the array, use forEach instead to iterate over the array.some
You don't need to use
return in the arrow-function, but since you are returning an object you must enclose it in parentheses (or it will be interpreted as a statement). key => ({type:"error"}) works, key => {type:"error"} doesn't, key => {return {type:"error"}} works but is longer to type..Another alternative is to use for ... in to traverse the object properties of err.errors:
Example:
const input = {"err":{"errors":{"last_name":{"message":"Path `last_name` is required.","name":"ValidatorError","properties":{"message":"Path `last_name` is required.","type":"required","path":"last_name"},"kind":"required","path":"last_name"},"first_name":{"message":"Path `first_name` is required.","name":"ValidatorError","properties":{"message":"Path `first_name` is required.","type":"required","path":"first_name"},"kind":"required","path":"first_name"},"password":{"message":"Path `password` (`iam`) is shorter than the minimum allowed length (6).","name":"ValidatorError","properties":{"message":"Path `password` (`iam`) is shorter than the minimum allowed length (6).","type":"minlength","minlength":6,"path":"password","value":"iam"},"kind":"minlength","path":"password","value":"iam"}},"_message":"User validation failed","message":"User validation failed: last_name: Path `last_name` is required., first_name: Path `first_name` is required., password: Path `password` (`iam`) is shorter than the minimum allowed length (6).","name":"ValidationError"}};
for (const k in input.err.errors)
{
const properties = input.err.errors[k].properties;
console.log("Error for " + k);
console.log("> Type: " + properties.type);
console.log("> Path: " + properties.path);
console.log("> Message: " + properties.message);
}.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}
answered May 19, 2019 at 18:44
Shidersz
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5 Comments
Shidersz
@some But, to use
for ... of I will have to do something like for (k of Object.keys(input.err.errors)) since it won't work directly over the object. And in this case, whit an array of keys, I will prefer to use built-in array methods like shown on the other answer.some
Use
for (const [key,value] of Object.entries(input.err.errors)) and instead of making lookups in input.err.errors[k] every time, use the variables key or value (or what you called them)Shidersz
@some Ok, it is another alternative, but not what I have tried to show. I just tried to show how to traverse some object directly, not converting first to an array of
keys or entries.some
Look at your code. You use
input.err.errors[k] twice. And you would have used it three times if you also printed the message. Every time you do input.err.errors[k] you make a lookup. At least save that as a constant for each iteration. const value = input.err.errors[k] instead of making the exact same lookup multiple times. It is not premature optimization. It is less to type, less chance to make a typo, easier to change if the path changes.lang-js