Viewing github.com/facebook/react/scripts/rollup/utils.js

```
'use strict';
```
```
const ncp = require('ncp').ncp;
```
```
const path = require('path');
```
```
const mkdirp = require('mkdirp');
```
```
const rimraf = require('rimraf');
```

const exec = require('child_process').exec;

```
const targz = require('targz');
```
```
function asyncCopyTo(from, to) {
```

  return asyncMkDirP(path.dirname(to)).then(

```
    () =>
```

      new Promise((resolve, reject) => {

```
        ncp(from, to, error => {
```
```
          if (error) {
```

            // Wrap to have a useful stack trace.

```
            reject(new Error(error));
```
```
          } else {
```

            // Wait for copied files to exist; ncp() sometimes completes prematurely.

            // For more detail, see github.com/facebook/react/issues/22323

            // Also github.com/AvianFlu/ncp/issues/127

```
            setTimeout(resolve, 10);
```
```
          }
```
```
        });
```
```
      })
```
```
  );
```
```
}
```

function asyncExecuteCommand(command) {

  return new Promise((resolve, reject) =>

```
    exec(command, (error, stdout) => {
```
```
      if (error) {
```
```
        reject(error);
```
```
        return;
```
```
      }
```
```
      resolve(stdout);
```
```
    })
```
```
  );
```
```
}
```
```
function asyncExtractTar(options) {
```

  return new Promise((resolve, reject) =>

    targz.decompress(options, error => {

```
      if (error) {
```
```
        reject(error);
```
```
        return;
```
```
      }
```
```
      resolve();
```
```
    })
```
```
  );
```
```
}
```
```
function asyncMkDirP(filepath) {
```

  return new Promise((resolve, reject) =>

```
    mkdirp(filepath, error => {
```
```
      if (error) {
```
```
        reject(error);
```
```
        return;
```
```
      }
```
```
      resolve();
```
```
    })
```
```
  );
```
```
}
```
```
function asyncRimRaf(filepath) {
```

  return new Promise((resolve, reject) =>

```
    rimraf(filepath, error => {
```
```
      if (error) {
```
```
        reject(error);
```
```
        return;
```
```
      }
```
```
      resolve();
```
```
    })
```
```
  );
```
```
}
```
```
function resolvePath(filepath) {
```
```
  if (filepath[0] === '~') {
```

    return path.join(process.env.HOME, filepath.slice(1));

```
  } else {
```
```
    return path.resolve(filepath);
```
```
  }
```
```
}
```
```
module.exports = {
```
```
  asyncCopyTo,
```
```
  resolvePath,
```
```
  asyncExecuteCommand,
```
```
  asyncExtractTar,
```
```
  asyncMkDirP,
```
```
  asyncRimRaf,
```
```
};
```

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