Unexpected end of JSON input - Hyperledger Fabric while using putState()

Question

async changeCarOwner(ctx, carNumber, newOwner) {

        const carAsBytes = await ctx.stub.getState(carNumber); 
        if (!carAsBytes || carAsBytes.length === 0) {
            throw new Error(`${carNumber} does not exist`);
        }
        const car = JSON.parse(carAsBytes.toString());
        car.owner = newOwner

        await ctx.stub.putState(carNumber, Buffer.from(JSON.stringify(car)));

    }

}

I keep getting an error: Unexpected end of JSON input. Why? I am trying to update an existing key-value pair in couchDb using the above code.

score 1 · Accepted Answer · answered Mar 03 '19 at 19:19

1

This error happens at this line:

const car = JSON.parse(carAsBytes.toString());

It is due to the fact that carAsBytes.toString() does not evaluates to a properly formatted JSON string. The code you show seems fine, but the error is coming from elsewhere in your code.

Debugging tip: use the debugger statement to examine variables before the faulty line, simply add a console.log(carAsBytes.toString()) before it.

answered Mar 03 '19 at 19:19

Nino Filiu

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That helped! Thank you. – Yash Damani Mar 04 '19 at 04:22
@Roby it's the one I wrote. What are you missing? – Nino Filiu Apr 06 '19 at 19:55
@NinoFiliu struggle with retrival, in my chaincode function i use `const item = await ctx.stub.getState(key); return item;` But can parse back with JSON.parse – Roby Apr 07 '19 at 06:40

Unexpected end of JSON input - Hyperledger Fabric while using putState()

1 Answers1