forked from babel/babel
/
scope.js
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scope.js
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import traverse, { NodePath } from "../lib";
import { parse } from "@babel/parser";
import * as t from "@babel/types";
function getPath(code, options): NodePath<t.Program> {
const ast =
typeof code === "string" ? parse(code, options) : createNode(code);
let path;
traverse(ast, {
Program: function (_path) {
path = _path;
_path.stop();
},
});
return path;
}
function getIdentifierPath(code) {
const ast = parse(code);
let nodePath;
traverse(ast, {
Identifier: function (path) {
nodePath = path;
path.stop();
},
});
return nodePath;
}
function createNode(node) {
const ast = t.file(t.program(Array.isArray(node) ? node : [node]));
// This puts the path into the cache internally
// We afterwards traverse ast, as we need to start traversing
// at the File node and not the Program node
NodePath.get({
hub: {
buildError: (_, msg) => new Error(msg),
},
parentPath: null,
parent: ast,
container: ast,
key: "program",
}).setContext();
return ast;
}
describe("scope", () => {
describe("binding paths", () => {
it("function declaration id", function () {
expect(
getPath("function foo() {}").scope.getBinding("foo").path.type,
).toBe("FunctionDeclaration");
});
it("function expression id", function () {
expect(
getPath("(function foo() {})")
.get("body")[0]
.get("expression")
.scope.getBinding("foo").path.type,
).toBe("FunctionExpression");
});
it("function param", function () {
expect(
getPath("(function (foo) {})")
.get("body")[0]
.get("expression")
.scope.getBinding("foo").path.type,
).toBe("Identifier");
});
describe("function parameter expression", function () {
it("should not have visibility of declarations inside function body", () => {
expect(
getPath(
`var a = "outside"; (function foo(b = a) { let a = "inside" })`,
)
.get("body.1.expression.params.0")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
});
it("should have visibility on parameter bindings", () => {
expect(
getPath(`var a = "outside"; (function foo(b = a, a = "inside") {})`)
.get("body.1.expression.params.0")
.scope.getBinding("a").path.node.right.value,
).toBe("inside");
});
});
describe("import declaration", () => {
it.each([
[
"import default",
"import foo from 'foo';(foo)=>{}",
"foo",
"ImportDefaultSpecifier",
],
[
"import named default",
"import { default as foo } from 'foo';(foo)=>{}",
"foo",
"ImportSpecifier",
],
[
"import named",
"import { foo } from 'foo';(foo)=>{}",
"foo",
"ImportSpecifier",
],
[
"import named aliased",
"import { _foo as foo } from 'foo';(foo)=>{}",
"foo",
"ImportSpecifier",
],
[
"import namespace",
"import * as foo from 'foo';(foo)=>{}",
"foo",
"ImportNamespaceSpecifier",
],
])("%s", (testTitle, source, bindingName, bindingNodeType) => {
expect(
getPath(source, { sourceType: "module" }).scope.getBinding(
bindingName,
).path.type,
).toBe(bindingNodeType);
});
});
describe("export declaration", () => {
it.each([
[
"export default function",
"export default function foo(foo) {}",
"foo",
"FunctionDeclaration",
],
[
"export default class",
"export default class foo extends function foo () {} {}",
"foo",
"ClassDeclaration",
],
[
"export named default",
"export const foo = function foo(foo) {};",
"foo",
"VariableDeclarator",
],
[
"export named default",
"export const [ { foo } ] = function foo(foo) {};",
"foo",
"VariableDeclarator",
],
])("%s", (testTitle, source, bindingName, bindingNodeType) => {
expect(
getPath(source, { sourceType: "module" }).scope.getBinding(
bindingName,
).path.type,
).toBe(bindingNodeType);
});
});
describe("computed method key", () => {
describe("should not have visibility of declarations inside method body", () => {
it("when path is computed key", () => {
expect(
getPath(`var a = "outside"; ({ [a]() { let a = "inside" } })`)
.get("body.1.expression.properties.0.key")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
expect(
getPath(
`var a = "outside"; class foo { [a]() { let a = "inside" } }`,
)
.get("body.1.body.body.0.key")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
});
it("when path is in nested scope which is computed key", () => {
expect(
getPath(`var a = "outside"; ({ [() => a]() { let a = "inside" } })`)
.get("body.1.expression.properties.0.key.body")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
expect(
getPath(
`var a = "outside"; class foo { [() => a]() { let a = "inside" } }`,
)
.get("body.1.body.body.0.key.body")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
});
it("when path is in nested scope within computed key", () => {
expect(
getPath(
`var a = "outside"; ({ [(() => a)() + ""]() { let a = "inside" } })`,
)
.get("body.1.expression.properties.0.key.left.callee.body")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
expect(
getPath(
`var a = "outside"; class foo { [(() => a)() + ""]() { let a = "inside" } }`,
)
.get("body.1.body.body.0.key.left.callee.body")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
});
});
it("should not have visibility on parameter bindings", () => {
expect(
getPath(`var a = "outside"; ({ [a](a = "inside") {} })`)
.get("body.1.expression.properties.0.key")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
expect(
getPath(`var a = "outside"; class foo { [a](a = "inside") {} }`)
.get("body.1.body.body.0.key")
.scope.getBinding("a").path.node.init.value,
).toBe("outside");
});
});
it("variable declaration", function () {
expect(getPath("var foo = null;").scope.getBinding("foo").path.type).toBe(
"VariableDeclarator",
);
expect(
getPath("var { foo } = null;").scope.getBinding("foo").path.type,
).toBe("VariableDeclarator");
expect(
getPath("var [ foo ] = null;").scope.getBinding("foo").path.type,
).toBe("VariableDeclarator");
expect(
getPath("var { bar: [ foo ] } = null;").scope.getBinding("foo").path
.type,
).toBe("VariableDeclarator");
});
it("declare var", function () {
expect(
getPath("declare var foo;", { plugins: ["flow"] }).scope.getBinding(
"foo",
).path.type,
).toBe("DeclareVariable");
});
it("declare function", function () {
expect(
getPath("declare function foo(): void;", {
plugins: ["flow"],
}).scope.getBinding("foo").path.type,
).toBe("DeclareFunction");
});
it("declare module", function () {
expect(
getPath("declare module foo {};", {
plugins: ["flow"],
}).scope.getBinding("foo").path.type,
).toBe("DeclareModule");
});
it("declare type alias", function () {
expect(
getPath("declare type foo = string;", {
plugins: ["flow"],
}).scope.getBinding("foo").path.type,
).toBe("DeclareTypeAlias");
});
it("declare opaque type", function () {
expect(
getPath("declare opaque type foo;", {
plugins: ["flow"],
}).scope.getBinding("foo").path.type,
).toBe("DeclareOpaqueType");
});
it("declare interface", function () {
expect(
getPath("declare interface Foo {};", {
plugins: ["flow"],
}).scope.getBinding("Foo").path.type,
).toBe("DeclareInterface");
});
it("type alias", function () {
expect(
getPath("type foo = string;", {
plugins: ["flow"],
}).scope.getBinding("foo").path.type,
).toBe("TypeAlias");
});
it("opaque type alias", function () {
expect(
getPath("opaque type foo = string;", {
plugins: ["flow"],
}).scope.getBinding("foo").path.type,
).toBe("OpaqueType");
});
it("interface", function () {
expect(
getPath("interface Foo {};", {
plugins: ["flow"],
}).scope.getBinding("Foo").path.type,
).toBe("InterfaceDeclaration");
});
it("import type", function () {
expect(
getPath("import type {Foo} from 'foo';", {
plugins: ["flow"],
}).scope.getBinding("Foo").path.type,
).toBe("ImportSpecifier");
});
it("variable constantness", function () {
expect(getPath("var a = 1;").scope.getBinding("a").constant).toBe(true);
expect(getPath("var a = 1; a = 2;").scope.getBinding("a").constant).toBe(
false,
);
expect(getPath("var a = 1, a = 2;").scope.getBinding("a").constant).toBe(
false,
);
expect(
getPath("var a = 1; var a = 2;").scope.getBinding("a").constant,
).toBe(false);
});
it("purity", function () {
expect(
getPath("({ x: 1, foo() { return 1 } })")
.get("body")[0]
.get("expression")
.isPure(),
).toBeTruthy();
expect(
getPath("class X { get foo() { return 1 } }")
.get("body")[0]
.get("expression")
.isPure(),
).toBeFalsy();
expect(
getPath("`${a}`").get("body")[0].get("expression").isPure(),
).toBeFalsy();
expect(
getPath("let a = 1; `${a}`").get("body")[1].get("expression").isPure(),
).toBeTruthy();
expect(
getPath("let a = 1; `${a++}`")
.get("body")[1]
.get("expression")
.isPure(),
).toBeFalsy();
expect(
getPath("tagged`foo`").get("body")[0].get("expression").isPure(),
).toBeFalsy();
expect(
getPath("String.raw`foo`").get("body")[0].get("expression").isPure(),
).toBeTruthy();
});
test("label", function () {
expect(getPath("foo: { }").scope.getBinding("foo")).toBeUndefined();
expect(getPath("foo: { }").scope.getLabel("foo").type).toBe(
"LabeledStatement",
);
expect(getPath("foo: { }").scope.getLabel("toString")).toBeUndefined();
expect(
getPath(
`
foo: { }
`,
).scope.generateUid("foo"),
).toBe("_foo");
});
test("generateUid collision check with labels", function () {
expect(
getPath(
`
_foo: { }
`,
).scope.generateUid("foo"),
).toBe("_foo2");
expect(
getPath(
`
_foo: { }
_foo1: { }
_foo2: { }
`,
).scope.generateUid("foo"),
).toBe("_foo3");
});
it("reference paths", function () {
const path = getIdentifierPath("function square(n) { return n * n}");
const referencePaths = path.context.scope.bindings.n.referencePaths;
expect(referencePaths).toHaveLength(2);
expect(referencePaths[0].node.loc.start).toEqual({
line: 1,
column: 28,
});
expect(referencePaths[1].node.loc.start).toEqual({
line: 1,
column: 32,
});
});
describe("after crawl", () => {
it("modified function identifier available in function scope", () => {
const path = getPath("(function f(f) {})")
.get("body")[0]
.get("expression");
path.get("id").replaceWith(t.identifier("g"));
path.scope.crawl();
const binding = path.scope.getBinding("g");
expect(binding.kind).toBe("local");
});
it("modified function param available in function scope", () => {
const path = getPath("(function f(f) {})")
.get("body")[0]
.get("expression");
path.get("params")[0].replaceWith(t.identifier("g"));
path.scope.crawl();
const binding = path.scope.getBinding("g");
expect(binding.kind).toBe("param");
});
it("modified class identifier available in class expression scope", () => {
const path = getPath("(class c {})").get("body")[0].get("expression");
path.get("id").replaceWith(t.identifier("g"));
path.scope.crawl();
const binding = path.scope.getBinding("g");
expect(binding.kind).toBe("local");
});
it("modified class identifier available in class declaration scope", () => {
const path = getPath("class c {}").get("body")[0];
path.get("id").replaceWith(t.identifier("g"));
path.scope.crawl();
const binding = path.scope.getBinding("g");
expect(binding.kind).toBe("let");
});
});
it("class identifier available in class scope after crawl", function () {
const path = getPath("class a { build() { return new a(); } }");
path.scope.crawl();
let referencePaths = path.scope.bindings.a.referencePaths;
expect(referencePaths).toHaveLength(1);
referencePaths = path.get("body[0]").scope.bindings.a.referencePaths;
expect(referencePaths).toHaveLength(1);
expect(path.scope.bindings.a).toBe(path.get("body[0]").scope.bindings.a);
});
it("references after re-crawling", function () {
const path = getPath("function Foo() { var _jsx; }");
path.scope.crawl();
path.scope.crawl();
expect(path.scope.references._jsx).toBeTruthy();
});
test("generateUid collision check after re-crawling", function () {
const path = getPath("function Foo() { var _jsx; }");
path.scope.crawl();
path.scope.crawl();
expect(path.scope.generateUid("jsx")).toBe("_jsx2");
});
test("generateUid collision check after re-crawling (function expression local id)", function () {
const path = getPath("var fn = function _name(){}");
path.scope.crawl();
path.scope.crawl();
expect(path.scope.generateUid("name")).toBe("_name2");
});
test("generateUid collision check after re-crawling (function params)", function () {
const path = getPath("[].map(_unicorn => [_unicorn])");
path.scope.crawl();
path.scope.crawl();
expect(path.scope.generateUid("unicorn")).toBe("_unicorn2");
});
test("generateUid collision check after re-crawling (catch clause)", function () {
const path = getPath("try {} catch (_err) {}");
path.scope.crawl();
path.scope.crawl();
expect(path.scope.generateUid("err")).toBe("_err2");
});
test("generateUid collision check after re-crawling (class expression local id)", function () {
const path = getPath("var C = class _Cls{}");
path.scope.crawl();
path.scope.crawl();
expect(path.scope.generateUid("Cls")).toBe("_Cls2");
});
it("re-exports are not references", () => {
const path = getPath("export { x } from 'y'", {
sourceType: "module",
});
expect(path.scope.hasGlobal("x")).toBe(false);
});
});
describe("duplicate bindings", () => {
/*
* These tests do not use the parser as the parser has
* its own scope tracking and we want to test the scope tracking
* of traverse here and see if it handles duplicate bindings correctly
*/
describe("catch", () => {
// try {} catch (e) { let e; }
const createTryCatch = function (kind) {
return t.tryStatement(
t.blockStatement([]),
t.catchClause(
t.identifier("e"),
t.blockStatement([
t.variableDeclaration(kind, [
t.variableDeclarator(t.identifier("e"), t.stringLiteral("1")),
]),
]),
),
);
};
["let", "const"].forEach(name => {
it(name, () => {
const ast = createTryCatch(name);
expect(() => getPath(ast)).toThrowErrorMatchingSnapshot();
});
});
it("var", () => {
const ast = createTryCatch("var");
expect(() => getPath(ast)).not.toThrow();
});
});
["let", "const"].forEach(name => {
it(`${name} and function in sub scope`, () => {
const ast = [
t.variableDeclaration(name, [
t.variableDeclarator(t.identifier("foo")),
]),
t.blockStatement([
t.functionDeclaration(
t.identifier("foo"),
[],
t.blockStatement([]),
),
]),
];
expect(() => getPath(ast)).not.toThrow();
});
});
describe("global", () => {
// node1, node2, success
// every line will run 2 tests `node1;node2;` and `node2;node1;`
// unless node1 === node2
const cases = [
["const", "let", false],
["const", "const", false],
["const", "function", false],
["const", "class", false],
["const", "var", false],
["let", "let", false],
["let", "class", false],
["let", "function", false],
["let", "var", false],
["var", "class", false],
["var", "function", true],
["var", "var", true],
["class", "function", false],
["class", "class", false],
["function", "function", true],
];
const createNode = function (kind) {
switch (kind) {
case "let":
case "const":
case "var":
return t.variableDeclaration(kind, [
t.variableDeclarator(t.identifier("foo")),
]);
case "class":
return t.classDeclaration(
t.identifier("foo"),
null,
t.classBody([]),
);
case "function":
return t.functionDeclaration(
t.identifier("foo"),
[],
t.blockStatement([]),
);
}
};
const createAST = function (kind1, kind2) {
return [createNode(kind1), createNode(kind2)];
};
for (const [kind1, kind2, success] of cases) {
it(`${kind1}/${kind2}`, () => {
const ast = createAST(kind1, kind2);
if (success) {
expect(() => getPath(ast)).not.toThrow();
} else {
expect(() => getPath(ast)).toThrowErrorMatchingSnapshot();
}
});
if (kind1 !== kind2) {
// todo: remove the if allowed
if (kind1 === "const" && (kind2 === "function" || kind2 === "var")) {
continue;
}
it(`${kind2}/${kind1}`, () => {
const ast = createAST(kind2, kind1);
if (success) {
expect(() => getPath(ast)).not.toThrow();
} else {
expect(() => getPath(ast)).toThrowErrorMatchingSnapshot();
}
});
}
}
});
});
});