function and test case to split a string by commas

split-by-comma.js

#!/usr/bin/env node

function splitByComma(string) {
    string = string.replace(/^\s*/,"")
    string = string.replace(/\s*$/,"")
    
    var result = string.split(/\s*,\s*/)
    if (result.length == 1) {
        if (result[0] == "") {
            return []
        }
    }
    
    return result
}

failures = 0

function test(a, b, message) {
    original_b = b
    b = splitByComma(b)
    
    // console.log("splitByComma('" + original_b + "'): ", b)
    
    if (a.length != b.length) {
        console.log("fail because lengths different: " + message)
        failures++
        return
    }
    
    for (var i=0; i<a.length; i++) {
        if (a[i] != b[i]) {
            console.log("fail because element at index " + i + " different: " + message)
            failures++
            return
        }
    }
    
}

test([],                    "",                   "empty string")
test([],                    " ",                  "space")
test([],                    "   ",                "spaces")
test([],                    "\t\t\t",             "tabs")
test(["a"],                 "a",                  "a")
test(["a", ""],             "a,",                 "a, empty")
test(["", "a"],             ",a",                 "empty, a")
test(["a"],                 "\ta\t\t",            "spaces a")
test(["a", "b"],            "a,b",                "a,b")
test(["a", "b"],            "  a  ,  b  ",        "spaces a,b")
test(["a", "", "b"],        "  a  ,  , b  ",      "spaces a,empty,b")
test(["a", "", "b"],        "  a  ,, b  ",        "spaces a,skinny empty,b")
test(["a", "b"],            "a  ,  b",            "inner spaces a,b")
test(["a12", "b34", "c56"], "  a12  ,  b34,c56",  "spaces a12,b34,c56")

if (failures == 0) {
    console.log("all tests pass")
}
else {
    console.log("failed tests: " + failures)
}