Normalize Whitespace Plugin: add configuration via attributes

[plasticrake]

Added the ability to set configuration using data- attributes. Previously you could only set them via page-wide defaults.

It appeared there was some unused code with env.settings left over from PR #851. But without that PR/plugin you cannot set anything at the block-level.

Original Plugin Author: @zeitgeist87

[github-actions]

JS File Size Changes (gzipped)

A total of 1 files have changed, with a combined diff of +180 B (+16.5%).

file	master	pull	size diff	% diff
plugins/normalize-whitespace/prism-normalize-whitespace.min.js	1.09 KB	1.27 KB	+180 B	+16.5%

Generated by 🚫 dangerJS against 1d5d896

[RunDevelopment]

Thank you for the PR @plasticrake!

I think the idea is good, but we need to improve the implementation a little.

[plasticrake]

It is more strict parsing data-props. If a value is unexpected it is ignored. Boolean props set with <pre data-prop> are set to true.

const assert = require('assert').strict;

function t (value, settingType) {
  switch (settingType) {
    case 'boolean':
      value = (value === 'true' || value === '') || (value === 'false' ? false : undefined);
      break;
    case 'number':
      value = (value === '' ? undefined : (isNaN(+value) ? undefined : +value));
      break;
  }
  return value;
}

assert(t('', 'boolean') === true);
assert(t('true', 'boolean') === true);
assert(t('false', 'boolean') === false);
assert(t('invalid', 'boolean') === undefined);

assert(t('', 'number') === undefined);
assert(t('0', 'number') === 0);
assert(t('123', 'number') === 123);
assert(t('invalid', 'number') === undefined);
assert(t('123invalid456', 'number') === undefined);

[RunDevelopment]

Thank you for contributing @plasticrake!