← Errors
This SyntaxError is thrown by JSON.parse() when the string it receives is not valid JSON. 'Unexpected end of input' specifically means the string was cut off before the JSON structure was complete, or the string was empty.
Why it happens
- •Parsing an empty string, for example from a failed fetch that returned no body.
- •A network response was truncated before it was fully received.
- •A file or database field that stores JSON was accidentally saved as empty or partially written.
- •String concatenation or interpolation produced a malformed JSON string.
Examples
JavaScript
Code that triggers the error
const raw = ""; // empty string from a failed fetch
const data = JSON.parse(raw);
console.log(data);Error output
SyntaxError: Unexpected end of JSON input
How to fix it
Validate the string before parsing: check that it is non-empty and wrap JSON.parse() in a try/catch. When fetching JSON from an API, use response.json() instead of manually parsing response.text(), as it handles the Content-Type and empty-body cases more gracefully.
Fixed code
const raw = "";
try {
const data = JSON.parse(raw);
console.log(data);
} catch (err) {
if (err instanceof SyntaxError) {
console.error("Invalid JSON received:", raw);
}
}Related errors
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