html2unicode.js

/**
* Copyright 2012-2016, Plotly, Inc.
* All rights reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/


'use strict';

var toSuperScript = require('superscript-text');

var ENTITIES = {
  'mu': 'μ',
  'amp': '&',
  'lt': '<',
  'gt': '>'
};

function fixSuperScript(x) {
  var idx = 0;
  while((idx = x.indexOf('<sup>', idx)) >= 0) {
    var nidx = x.indexOf('</sup>', idx);
    if(nidx < idx) {
      break;
    }
    x = x.slice(0, idx) + toSuperScript(x.slice(idx+5, nidx)) + x.slice(nidx+6);
  }
  return x;
}

function fixBR(x) {
  return x.replace(/\<br\>/g, '\n');
}

function stripTags(x) {
  return x.replace(/\<.*\>/g, '');
}

function fixEntities(x) {
  var idx = 0;
  while((idx = x.indexOf('&', idx)) >= 0) {
    var nidx = x.indexOf(';', idx);
    if(nidx < idx) {
      idx += 1;
      continue;
    }
    var entity = ENTITIES[x.slice(idx+1, nidx)];
    if(entity) {
      x = x.slice(0, idx) + entity + x.slice(nidx+1);
    } else {
      x = x.slice(0, idx) + x.slice(nidx+1);
    }
  }
  return x;
}

function convertHTMLToUnicode(html) {
  return '' +
    fixEntities(
    stripTags(
    fixSuperScript(
    fixBR(
      html))));
}

module.exports = convertHTMLToUnicode;