Revert "simplify trim methods"

[eventualbuddha]

This reverts commit 7532328.

I discovered that this was causing problems after attempting to update rollup-plugin-commonjs to use the latest of all its dependencies, including magic-string. Updating from v0.10.0 to v0.11.1 produced the following error:

  1) rollup-plugin-commonjs generates a sourcemap:
     AssertionError: null == 'samples/sourcemap/main.js'
      at test.js:72:11
      at tryCatch (node_modules/rollup/dist/rollup.js:400:12)
      at invokeCallback (node_modules/rollup/dist/rollup.js:412:13)
      at publish (node_modules/rollup/dist/rollup.js:383:7)
      at flush (node_modules/rollup/dist/rollup.js:127:5)

I noticed that the source map differed between the different versions of magic-string:

# magic-string 0.10.0

'use strict';

function __commonjs(fn, module) { return module = { exports: {} }, fn(module, module.exports), module.exports; }

var require$$0 = 42;

var main = __commonjs(function (module) {
var foo = require$$0;
console.log( foo );
});

var main$1 = (main && typeof main === 'object' && 'default' in main ? main['default'] : main);

module.exports = main$1;
{ version: 3,
  file: 'bundle.js',
  sources: [ 'samples/sourcemap/foo.js', 'samples/sourcemap/main.js' ],
  sourcesContent: 
   [ 'export default 42;\n',
     'var foo = require( \'./foo\' );\nconsole.log( foo );\n' ],
  names: [],
  mappings: ';;;;iBAAe,EAAE,CAAC;;;ACAlB,IAAI,GAAG,GAAG,UAAkB,CAAC;AAC7B,OAAO,CAAC,GAAG,EAAE,GAAG,EAAE,CAAC;;;;;' }


# magic-string 0.11.1

'use strict';

function __commonjs(fn, module) { return module = { exports: {} }, fn(module, module.exports), module.exports; }

var require$$0 = 42;

var main = __commonjs(function (module) {
var foo = require$$0;
console.log( foo );
});

var main$1 = (main && typeof main === 'object' && 'default' in main ? main['default'] : main);

module.exports = main$1;
{ version: 3,
  file: 'bundle.js',
  sources: [ 'samples/sourcemap/foo.js', 'samples/sourcemap/main.js' ],
  sourcesContent: 
   [ 'export default 42;\n',
     'var foo = require( \'./foo\' );\nconsole.log( foo );\n' ],
  names: [],
  mappings: ';;;;iBAAe,EAAE,CAAC;;;ACAlB,IAAI,GAAG,GAAG,UAAkB;;;;;;' }

It appears the source map in v0.11.1 is a truncated version of the other one. I determined that this commit was the bad one by using git bisect and npm link to run the rollup-plugin-commonjs tests with each revision, using git bisect skip on a few commits in magic-string that failed to pass its own tests. After reverting the bad commit on top of the current master the tests for rollup-plugin-commonjs began to work again. I don't have enough context on magic-string to fix the underlying cause, but you probably do, @Rich-Harris. Let me know if you need more information!

[Rich-Harris]

Thanks for digging into this and figuring out what was happening with the sourcemaps. I've released an alternative fix (52f4740) as 0.11.3. I rewrote most of the library to support #14 (a new move() method), and didn't have sufficient tests for this – as of 0.11 the content is stored as a series of consecutive chunks rather than as the original string plus a few patches.

The context for this, incidentally, is that I spent the last few days working on a new ES2015 compiler, Bublé, which needs the ability to move chunks of code around within a file. There's also rollup-plugin-buble which I'll move over to the rollup organisation once everything's a bit more tested. This package is now built with it.