How Do I Effectively Check for Empty, Undefined, or Null Strings in JavaScript?

Empty, Undefined, or Null Strings in JavaScript

In JavaScript, handling empty or nonexistent strings can be tricky. Unlike languages like C#, there isn't a dedicated string.Empty property.

Checking for Truthiness

To check whether a string is truthy (not empty, not null, not undefined), use the following comparison:

if (strValue) {
    // strValue is not empty, `true`, `42`, `Infinity`, etc.
}

Checking for Falsiness

Conversely, to check for a falsy value (empty string, false, 0, null, undefined, etc.), use this comparison:

if (!strValue) {
    // strValue is empty, `false`, `0`, `null`, `undefined`, etc.
}

Checking for an Empty String Specifically

To strictly check for an empty string and nothing else, use the following comparison:

if (strValue === "") {
    // strValue is an empty string
}

Checking for Non-Empty Strings

To check for strings that are not empty, use the following comparison:

if (strValue !== "") {
    // strValue is not an empty string
}

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