require-yields.md

require-yields

• Options
• Context and settings
• Failing examples
• Passing examples

Requires that yields are documented.

Will also report if multiple @yields tags are present.

See the next, forceRequireNext, and nextWithGeneratorTag options for an option to expect a non-standard @next tag.

Options

• exemptedBy - Array of tags (e.g., ['type']) whose presence on the document block avoids the need for a @yields. Defaults to an array with inheritdoc. If you set this array, it will overwrite the default, so be sure to add back inheritdoc if you wish its presence to cause exemption of the rule.
• forceRequireYields - Set to true to always insist on @yields documentation for generators even if there are only expressionless yield statements in the function. May be desired to flag that a project is aware of an undefined/void yield. Defaults to false.
• contexts - Set this to an array of strings representing the AST context (or an object with context and comment properties) where you wish the rule to be applied. Overrides the default contexts (see below). Set to "any" if you want the rule to apply to any jsdoc block throughout your files (as is necessary for finding function blocks not attached to a function declaration or expression, i.e., @callback or @function (or its aliases @func or @method) (including those associated with an @interface). This rule will only apply on non-default contexts when there is such a tag present and the forceRequireYields option is set or if the withGeneratorTag option is set with a present @generator tag (since we are not checking against the actual yield values in these cases).
• withGeneratorTag - If a @generator tag is present on a block, require @yields/@yield. Defaults to true. See contexts to any if you want to catch @generator with @callback or such not attached to a function.
• next - If true, this option will insist that any use of a yield return value (e.g., const rv = yield; or const rv = yield value;) has a (non-standard) @next tag (in addition to any @yields tag) so as to be able to document the type expected to be supplied into the iterator (the Generator iterator that is returned by the call to the generator function) to the iterator (e.g., it.next(value)). The tag will not be expected if the generator function body merely has plain yield; or yield value; statements without returning the values. Defaults to false.
• forceRequireNext - Set to true to always insist on @next documentation even if there are no yield statements in the function or none return values. May be desired to flag that a project is aware of the expected yield return being undefined. Defaults to false.
• nextWithGeneratorTag - If a @generator tag is present on a block, require (non-standard ) @next (see next option). This will require using void or undefined in cases where generators do not use the next()-supplied incoming yield-returned value. Defaults to false. See contexts to any if you want to catch @generator with @callback or such not attached to a function.

Context and settings

Context	Generator functions (FunctionDeclaration, FunctionExpression; others when contexts option enabled)
Tags	yields
Aliases	yield
Recommended	true
Options	contexts, exemptedBy, forceRequireNext, forceRequireYields, next, nextWithGeneratorTag, withGeneratorTag
Settings	ignoreReplacesDocs, overrideReplacesDocs, augmentsExtendsReplacesDocs, implementsReplacesDocs

Failing examples

The following patterns are considered problems:

/**
 *
 */
function * quux (foo) {

  yield foo;
}
// Message: Missing JSDoc @yields declaration.

/**
 * @yields
 */
function * quux (foo) {

  const retVal = yield foo;
}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]
// Message: Missing JSDoc @next declaration.

/**
 * @yields
 */
function * quux (foo) {

  const retVal = yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]
// Message: Missing JSDoc @next declaration.

/**
 * @yields {void}
 */
function * quux () {
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireNext":true}]
// Message: Missing JSDoc @next declaration.

/**
 * @yields {void}
 */
function * quux () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireNext":true}]
// Message: Missing JSDoc @next declaration.

/**
 *
 */
function * quux (foo) {

  const a = yield foo;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux (foo) {
  yield foo;
}
// Settings: {"jsdoc":{"tagNamePreference":{"yields":"yield"}}}
// Message: Missing JSDoc @yield declaration.

/**
 * @yields
 */
function * quux (foo) {
  const val = yield foo;
}
// Settings: {"jsdoc":{"tagNamePreference":{"next":"yield-returns"}}}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]
// Message: Missing JSDoc @yield-returns declaration.

/**
 * @yields
 * @next
 */
function * quux () {
  const ret = yield 5;
}
// Settings: {"jsdoc":{"tagNamePreference":{"next":false}}}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]
// Message: Unexpected tag `@next`

/**
 *
 */
function * quux() {
  yield 5;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux() {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
const quux = async function * () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
async function * quux () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 * @function
 * @generator
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 * @callback
 * @generator
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 * @yields {undefined}
 * @yields {void}
 */
function * quux (foo) {

  return foo;
}
// Message: Found more than one @yields declaration.

/**
 * @yields
 */
function * quux () {

}
// Settings: {"jsdoc":{"tagNamePreference":{"yields":false}}}
// Message: Unexpected tag `@yields`

/**
 * @param foo
 */
function * quux (foo) {
  yield 'bar';
}
// "jsdoc/require-yields": ["error"|"warn", {"exemptedBy":["notPresent"]}]
// Message: Missing JSDoc @yields declaration.

/**
 * @param {array} a
 */
async function * foo(a) {
  return;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 * @param {array} a
 */
async function * foo(a) {
  yield Promise.all(a);
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

class quux {
  /**
   *
   */
  * quux () {
    yield;
  }
}
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"forceRequireYields":true}]
// Message: Missing JSDoc @yields declaration.

/**
 * @param {array} a
 */
async function * foo(a) {
  yield Promise.all(a);
}
// Message: Missing JSDoc @yields declaration.

/**
 * @generator
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"withGeneratorTag":true}]
// Message: Missing JSDoc @yields declaration.

/**
 * @generator
 * @yields
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"nextWithGeneratorTag":true}]
// Message: Missing JSDoc @next declaration.

/**
 *
 */
function * quux () {
  if (true) {
    yield;
  }
  yield true;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  try {
    yield true;
  } catch (err) {
  }
  yield;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  try {
  } finally {
    yield true;
  }
  yield;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  try {
    yield;
  } catch (err) {
  }
  yield true;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  try {
    something();
  } catch (err) {
    yield true;
  }
  yield;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  switch (true) {
  case 'abc':
    yield true;
  }
  yield;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  switch (true) {
  case 'abc':
    yield;
  }
  yield true;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  for (const i of abc) {
    yield true;
  }
  yield;
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  for (const a in b) {
    yield true;
  }
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  for (let i=0; i<n; i+=1) {
    yield true;
  }
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  while(true) {
    yield true
  }
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  do {
    yield true
  }
  while(true)
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  if (true) {
    yield true;
  }
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  var a = {};
  with (a) {
    yield true;
  }
}
// Message: Missing JSDoc @yields declaration.

/**
 *
 */
function * quux () {
  if (true) {
    yield;
  } else {
    yield true;
  }
  yield;
}
// Message: Missing JSDoc @yields declaration.

Passing examples

The following patterns are not considered problems:

/**
 * @yields Foo.
 */
function * quux () {

  yield foo;
}

/**
 * @yields Foo.
 */
function * quux () {

  yield foo;
}
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"]}]

/**
 *
 */
function * quux () {
}

/**
 *
 */
function * quux () {
  yield;
}

/**
 *
 */
function quux (bar) {
  bar.doSomething(function * (baz) {
    yield baz.corge();
  })
}

/**
 * @yields {Array}
 */
function * quux (bar) {
  yield bar.doSomething(function * (baz) {
    yield baz.corge();
  })
}

/**
 * @inheritdoc
 */
function * quux (foo) {
}

/**
 * @override
 */
function * quux (foo) {
}

/**
 * @constructor
 */
function * quux (foo) {
}

/**
 * @implements
 */
function * quux (foo) {
  yield;
}

/**
 * @override
 */
function * quux (foo) {

  yield foo;
}

/**
 * @class
 */
function * quux (foo) {
  yield foo;
}

/**
 * @yields {object}
 */
function * quux () {

  yield {a: foo};
}

/**
 * @yields {void}
 */
function * quux () {
}

/**
 * @yields {undefined}
 */
function * quux () {
}

/**
 * @yields {void}
 */
function quux () {
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/**
 * @yields {void}
 * @next {void}
 */
function * quux () {
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireNext":true}]

/**
 * @yields {void}
 */
function * quux () {
  yield undefined;
}

/**
 * @yields {void}
 */
function * quux () {
  yield undefined;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/**
 * @yields {void}
 */
function * quux () {
  yield;
}

/**
 * @yields {void}
 */
function * quux () {
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/**
 * @yields {void}
 */
function * quux () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/** @type {SpecialIterator} */
function * quux () {
  yield 5;
}

/**
 * @yields {Something}
 */
async function * quux () {
}
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/**
 *
 */
async function * quux () {}

/**
 *
 */
const quux = async function * () {}

/**
 * @type {MyCallback}
 */
function * quux () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"exemptedBy":["type"]}]

/**
 * @param {array} a
 */
async function * foo (a) {
  yield;
}

/**
 *
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"]}]

/**
 * @function
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"]}]

/**
 * @function
 */
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/**
 * @callback
 */
// "jsdoc/require-yields": ["error"|"warn", {"forceRequireYields":true}]

/**
 * @generator
 */
// "jsdoc/require-yields": ["error"|"warn", {"withGeneratorTag":true}]

/**
 * @generator
 */
// "jsdoc/require-yields": ["error"|"warn", {"nextWithGeneratorTag":true}]

/**
 * @generator
 * @yields
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"withGeneratorTag":true}]

/**
 * @generator
 * @yields
 * @next
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"nextWithGeneratorTag":true}]

/**
 * @generator
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"withGeneratorTag":false}]

/**
 * @generator
 * @yields
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"nextWithGeneratorTag":false}]

/**
 * @yields
 */
function * quux (foo) {

  const a = yield foo;
}

/**
 * @yields
 * @next
 */
function * quux (foo) {
  let a = yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]

/**
 * @yields
 * @next
 */
function * quux (foo) {
  const a = yield foo;
}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]

/**
 *
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"nextWithGeneratorTag":true}]

/**
 *
 */
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"next":true}]

/**
 *
 */
function quux () {}
// "jsdoc/require-yields": ["error"|"warn", {"contexts":["any"],"next":true}]

/**
 * @yields {void}
 */
function * quux () {
  yield;
}
// "jsdoc/require-yields": ["error"|"warn", {"next":true}]

/**
 *
 */
function * quux (foo) {
  const a = function * bar () {
    yield foo;
  }
}