Nested ternaries are rewritten to mean something else than the original code

[anddoutoi]

This is due to not taking into account Operator Precedence when rewriting the code.

Run the following code in the console:

const foos = ['fubar']
const foo = undefined
const defaultFoos = ['snafu']
const fubar = foos ? foos : foo ? [foo] : defaultFoos
console.log(fubar)

Output is:

["fubar"]

Go to https://standardjs.com/demo.html, paste the code (or use this demo github gist link) and click Correct errors using --fix .

The code is rewritten to:

const foos = ['fubar']
const foo = undefined
const defaultFoos = ['snafu']
const fubar = foos || foo ? [foo] : defaultFoos
console.log(fubar)

Running this in a console outputs:

[undefined]

Standard has changed the actual meaning of the code.

[LinusU]

This is not good, would you mind filing a bug upstream with eslint, and then linking that issue here? Thanks

[anddoutoi]

Pasting the same code:

/* eslint-disable no-console */
/* eslint-env browser */
/*eslint no-unneeded-ternary: ["error", { "defaultAssignment": false }]*/
var foos = ['fubar']
var foo = undefined
var defaultFoos = ['snafu']
var fubar = foos ? foos : foo ? [foo] : defaultFoos
console.log(fubar)

in ESLints demo page produces the expected result. Maybe Standard is running an older version of ESLInt?

Maybe related:

• #866
• eslint/eslint#8507

[LinusU]

Ah, that might be it. There is an open PR here to fix it: #1267

ping @feross

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[LinusU]

This is fixed upstream and should be fixed in Standard 13, install with npm install standard@next