react-scripts
Version:
Configuration and scripts for Create React App.
65 lines (52 loc) • 2.15 kB
JavaScript
/**
* @fileoverview Ensures that the results of typeof are compared against a valid string
* @author Ian Christian Myers
*/
;
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
docs: {
description: "enforce comparing `typeof` expressions against valid strings",
category: "Possible Errors",
recommended: true
},
schema: [
{
type: "object",
properties: {
requireStringLiterals: {
type: "boolean"
}
},
additionalProperties: false
}
]
},
create(context) {
const VALID_TYPES = ["symbol", "undefined", "object", "boolean", "number", "string", "function"],
OPERATORS = ["==", "===", "!=", "!=="];
//--------------------------------------------------------------------------
// Public
//--------------------------------------------------------------------------
return {
UnaryExpression(node) {
if (node.operator === "typeof") {
const parent = context.getAncestors().pop();
if (parent.type === "BinaryExpression" && OPERATORS.indexOf(parent.operator) !== -1) {
const sibling = parent.left === node ? parent.right : parent.left;
if (sibling.type === "Literal") {
if (VALID_TYPES.indexOf(sibling.value) === -1) {
context.report(sibling, "Invalid typeof comparison value.");
}
} else if (context.options[0] && context.options[0].requireStringLiterals) {
context.report(sibling, "Typeof comparisons should be to string literals.");
}
}
}
}
};
}
};