Blame view
node_modules/eslint/lib/rules/consistent-this.js
4.6 KB
f7563de62
first commit
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 |
/**
* @fileoverview Rule to enforce consistent naming of "this" context variables
* @author Raphael Pigulla
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
docs: {
description: "enforce consistent naming when capturing the current execution context",
category: "Stylistic Issues",
recommended: false
},
schema: {
type: "array",
items: {
type: "string",
minLength: 1
},
uniqueItems: true
}
},
create(context) {
let aliases = [];
if (context.options.length === 0) {
aliases.push("that");
} else {
aliases = context.options;
}
/**
* Reports that a variable declarator or assignment expression is assigning
* a non-'this' value to the specified alias.
* @param {ASTNode} node - The assigning node.
* @param {string} alias - the name of the alias that was incorrectly used.
* @returns {void}
*/
function reportBadAssignment(node, alias) {
context.report({ node, message: "Designated alias '{{alias}}' is not assigned to 'this'.", data: { alias } });
}
/**
* Checks that an assignment to an identifier only assigns 'this' to the
* appropriate alias, and the alias is only assigned to 'this'.
* @param {ASTNode} node - The assigning node.
* @param {Identifier} name - The name of the variable assigned to.
* @param {Expression} value - The value of the assignment.
* @returns {void}
*/
function checkAssignment(node, name, value) {
const isThis = value.type === "ThisExpression";
if (aliases.indexOf(name) !== -1) {
if (!isThis || node.operator && node.operator !== "=") {
reportBadAssignment(node, name);
}
} else if (isThis) {
context.report({ node, message: "Unexpected alias '{{name}}' for 'this'.", data: { name } });
}
}
/**
* Ensures that a variable declaration of the alias in a program or function
* is assigned to the correct value.
* @param {string} alias alias the check the assignment of.
* @param {Object} scope scope of the current code we are checking.
* @private
* @returns {void}
*/
function checkWasAssigned(alias, scope) {
const variable = scope.set.get(alias);
if (!variable) {
return;
}
if (variable.defs.some(def => def.node.type === "VariableDeclarator" &&
def.node.init !== null)) {
return;
}
// The alias has been declared and not assigned: check it was
// assigned later in the same scope.
if (!variable.references.some(reference => {
const write = reference.writeExpr;
return (
reference.from === scope &&
write && write.type === "ThisExpression" &&
write.parent.operator === "="
);
})) {
variable.defs.map(def => def.node).forEach(node => {
reportBadAssignment(node, alias);
});
}
}
/**
* Check each alias to ensure that is was assinged to the correct value.
* @returns {void}
*/
function ensureWasAssigned() {
const scope = context.getScope();
aliases.forEach(alias => {
checkWasAssigned(alias, scope);
});
}
return {
"Program:exit": ensureWasAssigned,
"FunctionExpression:exit": ensureWasAssigned,
"FunctionDeclaration:exit": ensureWasAssigned,
VariableDeclarator(node) {
const id = node.id;
const isDestructuring =
id.type === "ArrayPattern" || id.type === "ObjectPattern";
if (node.init !== null && !isDestructuring) {
checkAssignment(node, id.name, node.init);
}
},
AssignmentExpression(node) {
if (node.left.type === "Identifier") {
checkAssignment(node, node.left.name, node.right);
}
}
};
}
};
|