wink-nlp/src/identify-marked-area.js

Developer friendly Natural Language Processing ✨

//     wink-nlp
//
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//
//     This file is part of “wink-nlp”.
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//

// ## identifyMarkedArea
/**
 *
 * Identifies the area to be marked within the detected entitity's span, which is
 * extracted as the value.
 *
 * @param {number[]} mark contains the target area to be extracted from within
 *                        the entitity's span, defined as `[ firstIndex, lastIndex ]`.
 * @param {number} length of the entity's span.
 * @return {number[]}     array containing the modifiers for the orginal span.
 * @private
*/
const identifyMarkedArea = function ( mark, length ) {
  // Length Minus 1.
  const lm1 = length - 1;
  let [ firstIndex, lastIndex ] = mark;

  if ( firstIndex < 0 ) firstIndex += length;
  firstIndex = Math.max( firstIndex, 0 );
  if ( firstIndex > lm1 ) firstIndex = 0;

  if ( lastIndex < 0 ) lastIndex += length;
  lastIndex = Math.min( lastIndex, lm1 );
  if ( lastIndex < firstIndex ) lastIndex = lm1;

  // The `lastIndex` manoeuvre is required to keep identical approach
  // being followed in `learnSinglePattern()` of automaton.js, where
  // the `firstIndex` **was** being added and the `lastIndex` **was** being
  // subtracted from the span of entity.
  lastIndex = length - lastIndex - 1;
  return [ firstIndex, lastIndex ];
}; // identifyMarkedArea()

module.exports = identifyMarkedArea;