Don't drop /*@__PURE__*/ comments

[Djaler]

Related to #221.

These comments should stay in the library build so client bundlers can respect them.

[evanw]

This is already the case. These comments are not dropped:

$ echo '/*@__PURE__*/fn()' | ./esbuild 
/* @__PURE__ */ fn();

[Djaler]

Sorry, I forgot to note that they are dropped if minify enabled

[Djaler]

const { transformSync } = require('esbuild');

console.log(transformSync(
    `
    const foo = /*@__PURE__*/ bar();
    
    export default foo;`,
    { minify: true },
).code);

// produces: 
// const o=bar();export default o;

[evanw]

It is expected behavior that they are dropped when minification is enabled. Minification is intended to produce production-ready assets to serve to users, and these comments would mean sending users many additional useless bytes. If you are generating code that is intended for another bundler to process, you can disable minification to preserve these comments and then enable minification in the other bundler so that the result is still minified.

[Djaler]

Makes sense, thanks