Why did JSHint miss my SyntaxError?

I accidentally had something like

var str = 'PS: ' otherStr 

(note the lack of a + between them)

...and my JSHint pre-commit hook didn't catch this. So the code got shipped and when it ran it gave SyntaxError: Unexpected identifier

I know that JSHint is ruing because if I just put str = instead of var str = I get an undefined issue. Am I missing some JSHint option? My .jshintrc looks like this:

{
    "asi": true,
    "expr": true,
    "loopfunc": true,
    "curly": false,
    "white": false,
    "undef": true,
    "node": true,
    "multistr": true,
    "predef": [
        "$",
        "FormBot",
        "socket",
        "confirm",
        "alert",
        "require",
        "__diame",
        "process",
        "exports",
        "console",
        "Buffer",
        "module"
    ]
}