JSON.isRawJSON()
Baseline
2025
Newly available
Since March 2025, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
The JSON.isRawJSON() static method tests whether a value is an object returned by JSON.rawJSON().
Syntax
JSON.isRawJSON(value)
Parameters
value-
The value to test.
Return value
true if value is created by JSON.rawJSON(); otherwise, false.
Description
"Raw JSON" objects, when serialized to JSON, are treated as if they are already a piece of JSON. Furthermore, because of the way JSON.rawJSON() works, the raw JSON is guaranteed to be syntactically valid JSON. For more information on the shape and behavior of raw JSON objects, see JSON.rawJSON(). This method exists to allow other serialization libraries to implement similar behavior to JSON.stringify() for raw JSON objects.
Examples
Using JSON.isRawJSON()
The following example demonstrates how to use JSON.isRawJSON() to test whether an object was returned by JSON.rawJSON(). It implements a custom serializer that serializes data to a YAML-like format.
function mySerializer(value, indent = "") {
if (typeof value !== "object" || value === null) {
return JSON.stringify(value);
}
if (JSON.isRawJSON(value)) {
return value.rawJSON;
}
const subIndent = `${indent} `;
if (Array.isArray(value)) {
return `- ${value.map((v) => mySerializer(v, subIndent)).join(`\n${indent}- `)}`;
}
return Object.entries(value)
.map(([key, value]) => {
const subValue = mySerializer(value, subIndent);
if (subValue.includes("\n")) {
return `${key}:\n${subIndent}${subValue}`;
}
return `${key}: ${subValue}`;
})
.join(`\n${indent}`);
}
console.log(
mySerializer({
name: "Josh",
userId: JSON.rawJSON("12345678901234567890"),
friends: [
{ name: "Alice", userId: JSON.rawJSON("9876543210987654321") },
{ name: "Bob", userId: JSON.rawJSON("56789012345678901234") },
],
}),
);
// name: "Josh"
// userId: 12345678901234567890
// friends:
// - name: "Alice"
// userId: 9876543210987654321
// - name: "Bob"
// userId: 56789012345678901234
If in the above example, the userId values were not created by JSON.rawJSON(), but passed as numbers directly, then we will get loss of precision upfront because of JS floating point precision limitations.
console.log(
mySerializer({
name: "Josh",
userId: 12345678901234567890,
friends: [
{ name: "Alice", userId: 9876543210987654321 },
{ name: "Bob", userId: 56789012345678901234 },
],
}),
);
// name: "Josh"
// userId: 12345678901234567000
// friends:
// - name: "Alice"
// userId: 9876543210987655000
// - name: "Bob"
// userId: 56789012345678900000
Specifications
| Specification |
|---|
| JSON.parse source text access # sec-json.israwjson |
Browser compatibility
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Legend
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