"Unexpected token in JSON at position 0"? - json

Question

I'm writing a node.js module which imports a JSON file:
const distDirPath = "c:/temp/dist/";
const targetPagePath = "c:/temp/index.html";
const cliJsonPath = "C:/CODE/MyApp/.angular-cli.json";
const fs = require('fs');
function deployAot()
{
var version = JSON.parse(fs.readFileSync(cliJsonPath, 'utf8')).version;
}
// export the module
module.exports = {
DeployAot: deployAot
};
I validated the contents of the json file above in https://jsonlint.com/ and it's valid json but the first line of code above in deployAot() returns the following error when I exec the node module:
"Unexpected token in JSON at position 0"
Here's the specific json:
https://jsonblob.com/cd6753d2-9e51-11e7-aa97-2f95b001b178
Any idea what the problem might be here?

Answer 1

As #cartant already mentioned in comments to the question, most probably you get a special character (Byte order mark) at the beginning of the file.
I would try to replace this
fs.readFileSync(cliJsonPath, 'utf8')
with this
fs.readFileSync(cliJsonPath, 'utf8').substring(1)
to get rid of the very first character from the string and would see what happens.
GitHub issue fs.readFileSync(filename, 'utf8') doesn't strip BOM markers
Recommendation from the issue:
Workaround:
body = body.replace(/^\uFEFF/, '');
After reading a UTF8 file where you are uncertain whether it may have a BOM marker in it.