Allow empty input by removing default if user enters backspace on empty input

[danmactough]

Strip surrounding quotes from input value; enable empty values

As mentioned a loooong time ago in #108, there's currently no way to input an empty value for an input with a default value.

But what if we allowed users to put quotes around their input values the way you would when setting a bash variable? And then the value would be set to the unquoted value.

In other words, when a user enters "foo" the value would be set to foo (without quotes).

This feels like expected behavior to me, and it would enable an empty value for an input with a default value, because "" would become an empty string.

Is this too magical or unexpected?

Would it be better to simply treat a value of "" or '' as a special case that should be transformed to an empty string?

I think some solution would be preferable to the current recommendation (adding an extra Y/N question).

UPDATED in line with comment to use backspace instead of stripping quotes.

[codecov]

Codecov Report

Merging #700 into master will decrease coverage by 0.04%.
The diff coverage is 85.71%.

@@            Coverage Diff             @@
##           master     #700      +/-   ##
==========================================
- Coverage   92.73%   92.69%   -0.05%     
==========================================
  Files          26       26              
  Lines        1033     1040       +7     
  Branches       19       19              
==========================================
+ Hits          958      964       +6     
- Misses         75       76       +1

Impacted Files	Coverage Δ
packages/inquirer/lib/prompts/input.js	97.77% <85.71%> (-2.23%)	⬇️

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[SBoudrias]

I think stripping the quotes might have side effet for other users who might need them. I guess you could allow spaces and strip them in the filter function.

Or maybe use backspace on empty answer to get rid of the default?

[danmactough]

Are you suggesting backspace would clear the default and rerender the prompt? That sounds great!

[SBoudrias]

Yeah, I think this would be more intuitive and more clearly communicate it with the user.

Want to send a PR?

[danmactough]

Yeah, I think this would be more intuitive and more clearly communicate it with the user.

Want to send a PR?

I've looked into using backspace, and I don't actually see how we could do it correctly.

It's possible to intercept the backspace here and remove the default value, but it's not possible to distinguish whether the user has hit backspace on an already empty line (for which we want to clear the default) or instead has hit backspace to remove the last previously-typed character to leave the line blank (which I don't think should trigger clearing the default.

Maybe an example will clarify.

If we change that onKeypress method to:

  onKeypress(event) {
    const { key } = event;
    // Empty the default when a user clears the input
    if (key.name === 'backspace' && !this.rl.line) {
      console.log('');
      console.log('key', key);
      console.log('this.rl.line', JSON.stringify(this.rl.line));
      this.opt.default = undefined;
    }

    this.render();
  }

$ node packages/inquirer/examples/input.js
? What's your first name # hit enter
? What's your last name (Doe) # hit backspace
key { sequence: '�',
  name: 'backspace',
  ctrl: false,
  meta: false,
  shift: false }
this.rl.line ""
? What's your last name # ^D

$ node packages/inquirer/examples/input.js
? What's your first name # hit enter
? What's your last name (Doe) a # hit a followed by backspace
key { sequence: '�',
  name: 'backspace',
  ctrl: false,
  meta: false,
  shift: false }
this.rl.line ""
? What's your last name # ^D

[SBoudrias]

I see the problem. I think on keypress, we can check the value of this.line. And if the line is empty then we set a flag like this.isEmpty or a relevant name. Then if this.isEmpty === true && key.name === 'backspace' we clear the default.

[danmactough]

@SBoudrias Ok, I updated this to use the backspace key instead of stripping surrounding quotes. I realized that we want to get this behavior even if the user has made no keypress before the backspace, so I implemented that little state tracking as hasInput instead of isEmpty.

[SBoudrias]

Thanks! The latest version looks great :)

[danmactough]

Thanks for your thoughtful feedback, Simon.

[orgads]

This works for a text field, but doesn't work for password.