syntax error when assigning to command result to variable - bash

Question

I'm doing some basic unit testing with the shunit2 unit test framework.
I'm getting the error " syntax error near unexpected token `nodeError=$( node "node_fake_returns/return_error.js" )" on the first line of my function. the function is as follows:
function testHandleNodeReturnError{
nodeError=$( node "./node_fake_returns/return_error.js" )
if [ grep -i "Error" <<< "$nodeError" ]; then
assertTrue "true"
fi
}
It is suppose to run a node script that returns an error message to stdout, then assign that output to a variable. Only this first line in the function is important.
I'm quite new to bash and I've messed with the formatting of this line, mostly just adding spaces in different places, but I can't seem to find what's causing the syntax error. This is probably pretty simple but if somebody could show me what might be wrong I would be greatful.
Thanks!

Answer 1

By pasting your code to shellcheck I was left with:
function testHandleNodeReturnError{
^-- SC1095: You need a space or linefeed between the function name and body.
Which is quite literal. You need a space there.
function testHandleNodeReturnError
Using function keyword is deprecated. Just use function_name() { function_body; }.
if [ grep -i "Error" <<< "$nodeError" ]; then
This is very wrong. This is outputting the content of nodeError variable to standard input of [ command. The [ is a command, a executable, just like grep, it's an alias to test program. Then it runs [ comamnd with grep, -i, "Error" and ] as 4 of it's arguments. You don't want that. If you want to check for Error string, just use grep's exit status:
So do:
testHandleNodeReturnError() {
nodeError=$(node "./node_fake_returns/return_error.js")
if grep -q -i "Error" <<<"$nodeError"; then
assertTrue "true"
fi
}