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<qhelp>

<overview>

<p>

Since JavaScript programs are not statically type checked, it is acceptable for a function to return

values of different types under different circumstances. In particular, a function can sometimes return

the special value <code>undefined</code>, while at other times it returns, say, a number. If this is

the desired behavior, it should be documented by explicitly returning <code>undefined</code> or

an expression that evaluates to <code>undefined</code> (such as <code>void 0</code>) rather than

using a return statement without an explicit return value.

</p>

</overview>

<recommendation>

<p>

Replace implicit return statements with return statements explicitly returning <code>undefined</code>

or <code>void 0</code> or a similar expression.

</p>

</recommendation>

<example>

<p>

In the following example, the function <code>solve_quad</code> computes one of the roots of a quadratic

equation given by the coefficients <code>a</code>, <code>b</code> and <code>c</code>. In cases where

there are no roots, it returns <code>undefined</code> by means of the implicit return statement on

line 3.

</p>

<sample src="examples/InconsistentReturn.js" />

<p>

It would be clearer to make this exceptional return value explicit as follows:

</p>

<sample src="examples/InconsistentReturnGood.js" />

</example>

<references>

<li>Mozilla Developer Network: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/return">Return</a>.</li>

</references>

</qhelp>