JSON source text access | Frontend Practical Guide

Browser support

Feature	Desktop				Mobile
Feature	Chrome	Edge	Firefox	Safari	Chrome Android	Safari iOS
`javascript.builtins.JSON.isRawJSON`	114	114	135	18.4	114	18.4
Built-in object
`JSON.parse.reviver parameter context argument` If a reviver is specified, the value computed by parsing is transformed before being returned. Specifically, the computed value and all its properties (in a depth-first fashion, beginning with the most nested properties and proceeding to the original value itself) are individually run through the reviver.	114	114	135	18.4	114	18.4
`JSON.rawJSON` The JSON.rawJSON() static method creates a "raw JSON" object containing a piece of JSON text. When serialized to JSON, the raw JSON object is treated as if it is already a piece of JSON. This text is required to be valid JSON.	114	114	135	18.4	114	18.4

1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)

JAVASCRIPT

JSON.parse('{"big": 12345678901234567890}', (key, value, { source }) => {
  if (key === 'big') return BigInt(source);
  return value;
});

Detect the API and fall back when the runtime does not support it yet.

JavaScript

Output

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Insert a prebuilt JSON fragment without double-encoding it.

JavaScript

Output

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See the difference between raw JSON insertion and a plain string field.

JavaScript

Output

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Precision-sensitive numbers

Retain the exact numeric source text when downstream logic must avoid precision loss.
Audit-friendly parsing

Compare parsed values with the original token text when traceability matters.

This is a niche parsing feature, so avoid it unless exact source preservation solves a real problem.
Extra parsing complexity is rarely justified for everyday configuration or API payloads.