no-unneeded-ternary.js
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/**
* @fileoverview Rule to flag no-unneeded-ternary
* @author Gyandeep Singh
* @copyright 2015 Gyandeep Singh. All rights reserved.
* @copyright 2015 Michael Ficarra. All rights reserved.
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = function(context) {
var options = context.options[0] || {};
var defaultAssignment = options.defaultAssignment !== false;
/**
* Test if the node is a boolean literal
* @param {ASTNode} node - The node to report.
* @returns {boolean} True if the its a boolean literal
* @private
*/
function isBooleanLiteral(node) {
return node.type === "Literal" && typeof node.value === "boolean";
}
/**
* Test if the node matches the pattern id ? id : expression
* @param {ASTNode} node - The ConditionalExpression to check.
* @returns {boolean} True if the pattern is matched, and false otherwise
* @private
*/
function matchesDefaultAssignment(node) {
return node.test.type === "Identifier" &&
node.consequent.type === "Identifier" &&
node.test.name === node.consequent.name;
}
return {
"ConditionalExpression": function(node) {
if (isBooleanLiteral(node.alternate) && isBooleanLiteral(node.consequent)) {
context.report(node, node.consequent.loc.start, "Unnecessary use of boolean literals in conditional expression");
} else if (!defaultAssignment && matchesDefaultAssignment(node)) {
context.report(node, node.consequent.loc.start, "Unnecessary use of conditional expression for default assignment");
}
}
};
};
module.exports.schema = [
{
"type": "object",
"properties": {
"defaultAssignment": {
"type": "boolean"
}
},
"additionalProperties": false
}
];