It is recommended to have documentation comments above, or right inside a function/class declaration. This helps developers, users and even the author understand the purpose of a code snippet or API function in the future.

NOTE: If you want to stop this issue from getting raised on certain constructs (arrow functions, class expressions, methods etc.), consider using the skipdoccoverage option under the analyzers.meta property in your .deepsource.toml file. For example, the following configuration will silence this issue for class expressions and method definitions:

[analyzers.meta]
    skip_doc_coverage = ["class-expression", "method-definition"]

Bad Practice

function sum(a, b) {
    return a + b;
}

Recommended

/**
 * Function to add two numbers
 * @param a The first number to add
 * @param b The second number to add
 * @returns The sum of two numbers
 */
function sum(a, b) {
    return a + b;
}