76 lines
2.0 KiB
JavaScript
76 lines
2.0 KiB
JavaScript
|
/**
|
||
|
|
* Ensures that the callback pattern is followed properly
|
||
|
|
* with an Error object (or undefined or null) in the first position.
|
||
|
|
*/
|
||
|
|
|
||
|
|
'use strict'
|
||
|
|
|
||
|
|
// ------------------------------------------------------------------------------
|
||
|
|
// Helpers
|
||
|
|
// ------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Determine if a node has a possiblity to be an Error object
|
||
|
|
* @param {ASTNode} node ASTNode to check
|
||
|
|
* @returns {boolean} True if there is a chance it contains an Error obj
|
||
|
|
*/
|
||
|
|
function couldBeError (node) {
|
||
|
|
switch (node.type) {
|
||
|
|
case 'Identifier':
|
||
|
|
case 'CallExpression':
|
||
|
|
case 'NewExpression':
|
||
|
|
case 'MemberExpression':
|
||
|
|
case 'TaggedTemplateExpression':
|
||
|
|
case 'YieldExpression':
|
||
|
|
return true // possibly an error object.
|
||
|
|
|
||
|
|
case 'AssignmentExpression':
|
||
|
|
return couldBeError(node.right)
|
||
|
|
|
||
|
|
case 'SequenceExpression':
|
||
|
|
var exprs = node.expressions
|
||
|
|
return exprs.length !== 0 && couldBeError(exprs[exprs.length - 1])
|
||
|
|
|
||
|
|
case 'LogicalExpression':
|
||
|
|
return couldBeError(node.left) || couldBeError(node.right)
|
||
|
|
|
||
|
|
case 'ConditionalExpression':
|
||
|
|
return couldBeError(node.consequent) || couldBeError(node.alternate)
|
||
|
|
|
||
|
|
default:
|
||
|
|
return node.value === null
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// ------------------------------------------------------------------------------
|
||
|
|
// Rule Definition
|
||
|
|
// ------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
module.exports = {
|
||
|
|
meta: {
|
||
|
|
docs: {
|
||
|
|
url: 'https://github.com/standard/eslint-plugin-standard#rules-explanations'
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
create: function (context) {
|
||
|
|
var callbackNames = context.options[0] || ['callback', 'cb']
|
||
|
|
|
||
|
|
function isCallback (name) {
|
||
|
|
return callbackNames.indexOf(name) > -1
|
||
|
|
}
|
||
|
|
|
||
|
|
return {
|
||
|
|
|
||
|
|
CallExpression: function (node) {
|
||
|
|
var errorArg = node.arguments[0]
|
||
|
|
var calleeName = node.callee.name
|
||
|
|
|
||
|
|
if (errorArg && !couldBeError(errorArg) && isCallback(calleeName)) {
|
||
|
|
context.report(node, 'Unexpected literal in error position of callback.')
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|