I want to parse a JSON Object that contains some value as a json string, note that I don't know those fields previously, so I can't do something like
obj[key]=JSON.parse(obj[key]). I am looking for an easy way to do that,
obj={
Name:"{\"FirstName\":\"Douglas\",\"LastName\":\"Crockford\"}"
}
And I want to get
{
Name:{
FirstName:"Douglas",
LastName:"Crockford"
}
}
If you want to get paradoxical about it, you can handle arbitrarily nested versions of this scenario using the "reviver parameter". Start by stringifying your object!
function parseJSON(k,v) {
try { return JSON.parse(v, parseJSON); }
catch(e) { return v; }
}
JSON.parse(JSON.stringify(obj), parseJSON);
Is that nifty, or is it just me?
We'll write a handy little utility which maps a function over object properties:
function mapObject(obj, fn) {
const result = {};
for (const prop in obj) result[prop] = fn(obj[prop], prop);
return result;
}
Now you can create an object with all the JSON values in the input parsed by just saying
mapObject(obj, JSON.parse)
If you want to guard against property values which are not valid JSON, then
function parseJSON(x) {
try { return JSON.parse(x); }
catch (e) { return x; }
}
and then
mapObject(obj, parseJSON)
You could use Object.keys(obj) to get the property names to allow you to use JSON.parse()
You can always try/pass on every key:
a = {
a: 1,
b: JSON.stringify({a: 1, b: 2}),
c: 'asdf'
}
console.log(a);
new_a = {}
Object.keys(a).map((key) => {
try {
new_a[key] = JSON.parse(a[key]);
} catch(err) {
new_a[key] = a[key];
}
})
console.log(new_a);
You can simply loop over all the keys:
obj={
Name: "{\"FisrtName\":\"Douglas\",\"LastName\":\"Crockford\"}",
Other: "This isn't JSON"
};
for (var key in obj) {
try {
obj[key] = JSON.parse(obj[key]);
} catch(err) {
// ignore error, just leave it alone
}
}
console.log(obj);
for, you use map.I have succeeded with : jsonData['key']['value']
If you have nested JSON.parse statements and need to have a nested JSON string, the inner string needs 3 backslashes to escape the double quote.
For example if this was the entry point of your application:
(async () => {
const event = JSON.parse(
JSON.parse(process.argv.slice(2)[0]).Message,
) as MyEvent;
processEvent(event);
})();
You would want to call this with a JSON string that looks something like this:
PS C:\_projects\eventProcessor> node dist\eventProcessor.js '{\"Message\":\"{\\\"myAttribute1\\\": \\\"myValue1\\\", \\\"myAttribute2\\\": \\\"myValue2\\\"}\" }'
Note that in windows the JSON string starts and ends with a single quote and has double quotes around the attributes and values within the object. Also, the inner string (i.e. Message object) needs to have the double quotes escaped with three (3) backslashes.
