Files
UglifyJS/test/mocha/yield.js
2017-12-30 03:27:26 +08:00

131 lines
4.5 KiB
JavaScript

var UglifyJS = require("../node");
var assert = require("assert");
describe("Yield", function() {
it("Should not delete statements after yield", function() {
var js = 'function *foo(bar) { yield 1; yield 2; return 3; }';
var result = UglifyJS.minify(js);
assert.strictEqual(result.code, 'function*foo(e){return yield 1,yield 2,3}');
});
it("Should not allow yield* followed by a semicolon in generators", function() {
var js = "function* test() {yield*\n;}";
var test = function() {
UglifyJS.parse(js);
}
var expect = function(e) {
return e instanceof UglifyJS.JS_Parse_Error &&
e.message === "Unexpected token: punc (;)";
}
assert.throws(test, expect);
});
it("Should not allow yield with next token star on next line", function() {
var js = "function* test() {yield\n*123;}";
var test = function() {
UglifyJS.parse(js);
}
var expect = function(e) {
return e instanceof UglifyJS.JS_Parse_Error &&
e.message === "Unexpected token: operator (*)";
}
assert.throws(test, expect);
});
it("Should be able to compress its expression", function() {
assert.strictEqual(
UglifyJS.minify("function *f() { yield 3-4; }", {compress: true}).code,
"function*f(){yield-1}"
);
});
it("Should keep undefined after yield without compression if found in ast", function() {
assert.strictEqual(
UglifyJS.minify("function *f() { yield undefined; yield; yield* undefined; yield void 0}", {compress: false}).code,
"function*f(){yield undefined;yield;yield*undefined;yield void 0}"
);
});
it("Should be able to drop undefined after yield if necessary with compression", function() {
assert.strictEqual(
UglifyJS.minify("function *f() { yield undefined; yield; yield* undefined; yield void 0}", {compress: true}).code,
"function*f(){yield,yield,yield*void 0,yield}"
);
});
var identifiers = [
// Fail in as_symbol
'import yield from "bar";',
'yield = 123;',
'yield: "123";',
'for(;;){break yield;}',
'for(;;){continue yield;}',
'function yield(){}',
'try { new Error("")} catch (yield) {}',
'var yield = "foo";',
'class yield {}',
// Fail in as_property_name
'var foo = {yield};',
];
it("Should not allow yield to be used as symbol, identifier or shorthand property outside generators in strict mode", function() {
function fail(e) {
return e instanceof UglifyJS.JS_Parse_Error &&
/^Unexpected yield identifier (?:as parameter )?inside strict mode/.test(e.message);
}
function test(input) {
return function() {
UglifyJS.parse(input);
}
}
identifiers.concat([
// Fail in as_symbol
"function foo(...yield){}",
// Fail in maybe_assign
'var foo = yield;',
'var foo = bar = yield',
]).map(function(code) {
return '"use strict"; ' + code;
}).forEach(function(code) {
assert.throws(test(code), fail, code);
});
});
it("Should not allow yield to be used as symbol, identifier or shorthand property inside generators", function() {
function fail(e) {
return e instanceof UglifyJS.JS_Parse_Error && [
"Unexpected token: operator (=)",
"Yield cannot be used as identifier inside generators",
].indexOf(e.message) >= 0;
}
function test(input) {
return function() {
UglifyJS.parse(input);
}
}
identifiers.map(function(code) {
return "function* f() { " + code + " }";
}).concat([
// Fail in as_symbol
"function* f(yield) {}",
]).forEach(function(code) {
assert.throws(test(code), fail, code);
});
});
it("Should allow yield to be used as class/object property name", function() {
var input = [
'"use strict";',
"({yield:42});",
"({yield(){}});",
"(class{yield(){}});",
"class C{yield(){}}",
].join("");
assert.strictEqual(UglifyJS.minify(input, { compress: false }).code, input);
});
});