eslint: no-plusplus set to 0 but still work

Question

In my project, I came across a confusing point about eslint.

currently, the eslint check report many no-plusplus error for the operation of ++ or --.

And in my project, most of such operations are in the for loop. So I check the eslint document, and want to disable the checking by following settings:

'no-plusplus': ['error', { "allowForLoopAfterthoughts": true }]

but the errors are still reported.

Then I tried 'no-plusplus': 0

But the errors are still there.

My eslint version is 3.x.

so what's wrong with my setting?