Is there a way to get my replacer called before an object's own toJSON
transforms it, so that I can work with the original object rather than its JSON-friendly form, without overriding the toJSON
on the object or its prototype, pre-processing the object, or writing my own version of JSON.stringify
?
For example: Suppose I want to serialize Date
instances differently than their normal serialization (which is toISOString
). (This question is not specific to Date
, this is just an example.) The problem is, my replacer doesn't see the Date
object, it sees a string (see snippet below) because Date.prototype.toJSON
is called before my replacer.
var obj = {
d: new Date()
};
snippet.log(getType(obj.d)); // "[object Date]"
var json = JSON.stringify(obj, function(key, value) {
if (key === "d") {
snippet.log(getType(value)); // "string" <== Want to see a Date here
}
return value;
});
function getType(value) {
var to = typeof value;
if (to === "object") {
to = Object.prototype.toString.call(value);
}
return to;
}
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<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>
Is there a way to get the replacer called first? I don't want to override Date.prototype.toJSON
, pre-process the object, or write my own JSON.stringify
, but I'm not seeing another way.
If I understand you correct this should do the trick, I'm pretty sure this
is always the object JSON.stringify
is currently iterating over:
var json = JSON.stringify(obj, function(key, value) {
if (key === "d") {
snippet.log(getType(this[key]));
}
return value;
});