When lowering optional chaining / nullish coalescing operator, the temporary variable declaration gets inject at the top of the function. Then, "use strict" becomes the non-first statement and that function becomes non-strict (sloppy) mode.
Input:
const foo = () => {
'use strict';
const f1 = function () {};
const f2 = () => {};
f1()?.foo;
f2()?.foo;
console.log(window.bar ?? 'foo');
};
const bar = function () {
'use strict';
const f1 = function () {};
const f2 = () => {};
f1()?.foo;
f2()?.foo;
console.log(window.bar ?? 'foo');
};Options: --target es2015
Actual output:
const foo = () => {
var _a, _b, _c;
"use strict";
const f1 = function() {
};
const f2 = () => {
};
(_a = f1()) == null ? void 0 : _a.foo;
(_b = f2()) == null ? void 0 : _b.foo;
console.log((_c = window.bar) != null ? _c : "foo");
};
const bar = function() {
var _a, _b, _c;
"use strict";
const f1 = function() {
};
const f2 = () => {
};
(_a = f1()) == null ? void 0 : _a.foo;
(_b = f2()) == null ? void 0 : _b.foo;
console.log((_c = window.bar) != null ? _c : "foo");
};Expected output:
const foo = () => {
"use strict";
var _a, _b, _c;
const f1 = function() {
};
const f2 = () => {
};
(_a = f1()) == null ? void 0 : _a.foo;
(_b = f2()) == null ? void 0 : _b.foo;
console.log((_c = window.bar) != null ? _c : "foo");
};
const bar = function() {
"use strict";
var _a, _b, _c;
const f1 = function() {
};
const f2 = () => {
};
(_a = f1()) == null ? void 0 : _a.foo;
(_b = f2()) == null ? void 0 : _b.foo;
console.log((_c = window.bar) != null ? _c : "foo");
};esbuild try
This bug seems to exist since at least 0.5.1.
related: vitejs/vite#14094
When lowering optional chaining / nullish coalescing operator, the temporary variable declaration gets inject at the top of the function. Then,
"use strict"becomes the non-first statement and that function becomes non-strict (sloppy) mode.Input:
Options:
--target es2015Actual output:
Expected output:
esbuild try
This bug seems to exist since at least 0.5.1.
related: vitejs/vite#14094