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javascriptstringperformancetrim

Redundant if statement?

Is the if statement in the following example redundant?

if (str[0] === ' ') {
  str = str.trimStart()
}

It seems unnecessary to me since trimStart() does not seem to have any negative effect on a string without a space at the beginning. Additionally, if the string does have a space at the beginning, you are running twice as many operations as needed.

Is the if statement ever necessary in situations like the one above?

Solution

  • The if is not necessary, but you should save the trimmed value somewhere, like

    str = str.trimStart();

    -- Edit --

    "Is the 'if' ever necessary...?"

    The test that you are doing in the original is redundant. But you might want to check that str has a value and/or check that this value is a string before calling trimStart(), like

    if (str && typeof str === 'string') ...