utils/fastdiff

@ckeditor/ckeditor5-utils/src/fastdiff

Functions

• fastDiff( oldText, newText ) → Arraymodule:utils/fastdiff.fastDiff

  static

  Finds position of the first and last change in the given strings and generates set of changes. Set of changes can be applied to the input text in order to transform it into the output text, for example:

  See source

  fastDiff( '12a', '12xyza' );
  // [ { index: 2, type: 'insert', values: [ 'x', 'y', 'z' ] } ]
  
  fastDiff( '12a', '12aa' );
  // [ { index: 3, type: 'insert', values: [ 'a' ] } ]
  
  fastDiff( '12xyza', '12a' );
  // [ { index: 2, type: 'delete', howMany: 3 } ]
  
  fastDiff( '12aa', '12a' );
  // [ { index: 3, type: 'delete', howMany: 1 } ]
  
  fastDiff( '12abc3', '2ab' );
  // [ { index: 0, type: 'insert', values: [ '2', 'a', 'b' ] }, { index: 3, type: 'delete', howMany: 6 } ]

  Using returned results you can modify oldText to transform it into newText:

  let input = '12abc3';
  const output = '2ab';
  const changes = fastDiff( input, output );
  
  changes.forEach( change => {
      if ( change.type == 'insert' ) {
          input = input.substring( 0, change.index ) + change.values.join( '' ) + input.substring( change.index );
      } else if ( change.type == 'delete' ) {
          input = input.substring( 0, change.index ) + input.substring( change.index + change.howMany );
      }
  } );
  
  input === output; // -> true

  The output format of this function is compatible with diffToChanges output format.

  Parameters

  oldText : String

  Input string.

  newText : String

  Input string.

  Returns

  Array

  Array of changes.