eslint/no-else-return Pedantic

🛠️ An auto-fix is available for this rule for some violations.

What it does

Disallow else blocks after return statements in if statements

Why is this bad?

If an if block contains a return statement, the else block becomes unnecessary. Its contents can be placed outside of the block.

function foo() {
  if (x) {
    return y;
  } else {
    return z;
  }
}

This rule is aimed at highlighting an unnecessary block of code following an if containing a return statement. As such, it will warn when it encounters an else following a chain of ifs, all of them containing a return statement.

Examples

allowElseIf: true

Examples of incorrect code for this rule:

function foo1() {
  if (x) {
    return y;
  } else {
    return z;
  }
}

function foo2() {
  if (x) {
    return y;
  } else if (z) {
    return w;
  } else {
    return t;
  }
}

function foo3() {
  if (x) {
    return y;
  } else {
    var t = "foo";
  }

  return t;
}

function foo4() {
  if (error) {
    return "It failed";
  } else {
    if (loading) {
      return "It's still loading";
    }
  }
}

// Two warnings for nested occurrences
function foo5() {
  if (x) {
    if (y) {
      return y;
    } else {
      return x;
    }
  } else {
    return z;
  }
}

Examples of correct code for this rule:

function foo1() {
  if (x) {
    return y;
  }

  return z;
}

function foo2() {
  if (x) {
    return y;
  } else if (z) {
    var t = "foo";
  } else {
    return w;
  }
}

function foo3() {
  if (x) {
    if (z) {
      return y;
    }
  } else {
    return z;
  }
}

function foo4() {
  if (error) {
    return "It failed";
  } else if (loading) {
    return "It's still loading";
  }
}

Configuration

This rule accepts a configuration object with the following properties:

allowElseIf

type: boolean

default: true

Whether to allow else if blocks after a return statement.

Examples of incorrect code for this rule with allowElseIf: false:

function foo() {
  if (error) {
    return "It failed";
  } else if (loading) {
    return "It's still loading";
  }
}

Examples of correct code for this rule with allowElseIf: false:

function foo() {
  if (error) {
    return "It failed";
  }

  if (loading) {
    return "It's still loading";
  }
}

How to use

To enable this rule in the CLI or using the config file, you can use:

CLI

oxlint --deny no-else-return

Config (.oxlintrc.json)

{
  "rules": {
    "no-else-return": "error"
  }
}

References

• Rule Source