@typescript-eslint/eslint-plugin
Version:
TypeScript plugin for ESLint
303 lines (302 loc) • 11.3 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
const scope_manager_1 = require("@typescript-eslint/scope-manager");
const utils_1 = require("@typescript-eslint/utils");
const util_1 = require("../util");
const referenceContainsTypeQuery_1 = require("../util/referenceContainsTypeQuery");
const SENTINEL_TYPE = /^(?:(?:Function|Class)(?:Declaration|Expression)|ArrowFunctionExpression|CatchClause|ImportDeclaration|ExportNamedDeclaration)$/;
/**
* Parses a given value as options.
*/
function parseOptions(options) {
let functions = true;
let classes = true;
let enums = true;
let variables = true;
let typedefs = true;
let ignoreTypeReferences = true;
let allowNamedExports = false;
if (typeof options === 'string') {
functions = options !== 'nofunc';
}
else if (typeof options === 'object' && options != null) {
functions = options.functions !== false;
classes = options.classes !== false;
enums = options.enums !== false;
variables = options.variables !== false;
typedefs = options.typedefs !== false;
ignoreTypeReferences = options.ignoreTypeReferences !== false;
allowNamedExports = options.allowNamedExports !== false;
}
return {
allowNamedExports,
classes,
enums,
functions,
ignoreTypeReferences,
typedefs,
variables,
};
}
/**
* Checks whether or not a given variable is a function declaration.
*/
function isFunction(variable) {
return variable.defs[0].type === scope_manager_1.DefinitionType.FunctionName;
}
/**
* Checks whether or not a given variable is a type declaration.
*/
function isTypedef(variable) {
return variable.defs[0].type === scope_manager_1.DefinitionType.Type;
}
/**
* Checks whether or not a given variable is a enum declaration.
*/
function isOuterEnum(variable, reference) {
return (variable.defs[0].type === scope_manager_1.DefinitionType.TSEnumName &&
variable.scope.variableScope !== reference.from.variableScope);
}
/**
* Checks whether or not a given variable is a class declaration in an upper function scope.
*/
function isOuterClass(variable, reference) {
return (variable.defs[0].type === scope_manager_1.DefinitionType.ClassName &&
variable.scope.variableScope !== reference.from.variableScope);
}
/**
* Checks whether or not a given variable is a variable declaration in an upper function scope.
*/
function isOuterVariable(variable, reference) {
return (variable.defs[0].type === scope_manager_1.DefinitionType.Variable &&
variable.scope.variableScope !== reference.from.variableScope);
}
/**
* Checks whether or not a given reference is a export reference.
*/
function isNamedExports(reference) {
const { identifier } = reference;
return (identifier.parent.type === utils_1.AST_NODE_TYPES.ExportSpecifier &&
identifier.parent.local === identifier);
}
/**
* Checks whether or not a given reference is a type reference.
*/
function isTypeReference(reference) {
return (reference.isTypeReference ||
(0, referenceContainsTypeQuery_1.referenceContainsTypeQuery)(reference.identifier));
}
/**
* Checks whether or not a given location is inside of the range of a given node.
*/
function isInRange(node, location) {
return !!node && node.range[0] <= location && location <= node.range[1];
}
/**
* Decorators are transpiled such that the decorator is placed after the class declaration
* So it is considered safe
*/
function isClassRefInClassDecorator(variable, reference) {
if (variable.defs[0].type !== scope_manager_1.DefinitionType.ClassName ||
variable.defs[0].node.decorators.length === 0) {
return false;
}
for (const deco of variable.defs[0].node.decorators) {
if (reference.identifier.range[0] >= deco.range[0] &&
reference.identifier.range[1] <= deco.range[1]) {
return true;
}
}
return false;
}
/**
* Checks whether or not a given reference is inside of the initializers of a given variable.
*
* @returns `true` in the following cases:
* - var a = a
* - var [a = a] = list
* - var {a = a} = obj
* - for (var a in a) {}
* - for (var a of a) {}
*/
function isInInitializer(variable, reference) {
if (variable.scope !== reference.from) {
return false;
}
let node = variable.identifiers[0].parent;
const location = reference.identifier.range[1];
while (node) {
if (node.type === utils_1.AST_NODE_TYPES.VariableDeclarator) {
if (isInRange(node.init, location)) {
return true;
}
if ((node.parent.parent.type === utils_1.AST_NODE_TYPES.ForInStatement ||
node.parent.parent.type === utils_1.AST_NODE_TYPES.ForOfStatement) &&
isInRange(node.parent.parent.right, location)) {
return true;
}
break;
}
else if (node.type === utils_1.AST_NODE_TYPES.AssignmentPattern) {
if (isInRange(node.right, location)) {
return true;
}
}
else if (SENTINEL_TYPE.test(node.type)) {
break;
}
node = node.parent;
}
return false;
}
exports.default = (0, util_1.createRule)({
name: 'no-use-before-define',
meta: {
type: 'problem',
docs: {
description: 'Disallow the use of variables before they are defined',
extendsBaseRule: true,
},
messages: {
noUseBeforeDefine: "'{{name}}' was used before it was defined.",
},
schema: [
{
oneOf: [
{
type: 'string',
enum: ['nofunc'],
},
{
type: 'object',
additionalProperties: false,
properties: {
allowNamedExports: {
type: 'boolean',
description: 'Whether to ignore named exports.',
},
classes: {
type: 'boolean',
description: 'Whether to ignore references to class declarations.',
},
enums: {
type: 'boolean',
description: 'Whether to check references to enums.',
},
functions: {
type: 'boolean',
description: 'Whether to ignore references to function declarations.',
},
ignoreTypeReferences: {
type: 'boolean',
description: 'Whether to ignore type references, such as in type annotations and assertions.',
},
typedefs: {
type: 'boolean',
description: 'Whether to check references to types.',
},
variables: {
type: 'boolean',
description: 'Whether to ignore references to variables.',
},
},
},
],
},
],
},
defaultOptions: [
{
allowNamedExports: false,
classes: true,
enums: true,
functions: true,
ignoreTypeReferences: true,
typedefs: true,
variables: true,
},
],
create(context, optionsWithDefault) {
const options = parseOptions(optionsWithDefault[0]);
/**
* Determines whether a given use-before-define case should be reported according to the options.
* @param variable The variable that gets used before being defined
* @param reference The reference to the variable
*/
function isForbidden(variable, reference) {
if (options.ignoreTypeReferences && isTypeReference(reference)) {
return false;
}
if (isFunction(variable)) {
return options.functions;
}
if (isOuterClass(variable, reference)) {
return options.classes;
}
if (isOuterVariable(variable, reference)) {
return options.variables;
}
if (isOuterEnum(variable, reference)) {
return options.enums;
}
if (isTypedef(variable)) {
return options.typedefs;
}
return true;
}
function isDefinedBeforeUse(variable, reference) {
return (variable.identifiers[0].range[1] <= reference.identifier.range[1] &&
!(reference.isValueReference && isInInitializer(variable, reference)));
}
/**
* Finds and validates all variables in a given scope.
*/
function findVariablesInScope(scope) {
scope.references.forEach(reference => {
const variable = reference.resolved;
function report() {
context.report({
node: reference.identifier,
messageId: 'noUseBeforeDefine',
data: {
name: reference.identifier.name,
},
});
}
// Skips when the reference is:
// - initializations.
// - referring to an undefined variable.
// - referring to a global environment variable (there're no identifiers).
// - located preceded by the variable (except in initializers).
// - allowed by options.
if (reference.init) {
return;
}
if (!options.allowNamedExports && isNamedExports(reference)) {
if (!variable || !isDefinedBeforeUse(variable, reference)) {
report();
}
return;
}
if (!variable) {
return;
}
if (variable.identifiers.length === 0 ||
isDefinedBeforeUse(variable, reference) ||
!isForbidden(variable, reference) ||
isClassRefInClassDecorator(variable, reference) ||
reference.from.type === utils_1.TSESLint.Scope.ScopeType.functionType) {
return;
}
// Reports.
report();
});
scope.childScopes.forEach(findVariablesInScope);
}
return {
Program(node) {
findVariablesInScope(context.sourceCode.getScope(node));
},
};
},
});