overleaf/services/document-updater/app/coffee/sharejs/text-composable-api.js

/*
 * decaffeinate suggestions:
 * DS101: Remove unnecessary use of Array.from
 * DS102: Remove unnecessary code created because of implicit returns
 * DS205: Consider reworking code to avoid use of IIFEs
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
// Text document API for text

let type;
if (typeof WEB !== 'undefined' && WEB !== null) {
  type = exports.types['text-composable'];
} else {
  type = require('./text-composable');
}

type.api = {
  provides: {'text':true},

  // The number of characters in the string
  'getLength'() { return this.snapshot.length; },

  // Get the text contents of a document
  'getText'() { return this.snapshot; },

  'insert'(pos, text, callback) {
    const op = type.normalize([pos, {'i':text}, (this.snapshot.length - pos)]);
    
    this.submitOp(op, callback);
    return op;
  },
  
  'del'(pos, length, callback) {
    const op = type.normalize([pos, {'d':this.snapshot.slice(pos, (pos + length))}, (this.snapshot.length - pos - length)]);

    this.submitOp(op, callback);
    return op;
  },

  _register() {
    return this.on('remoteop', function(op) {
      let pos = 0;
      return (() => {
        const result = [];
        for (let component of Array.from(op)) {
          if (typeof component === 'number') {
            result.push(pos += component);
          } else if (component.i !== undefined) {
            this.emit('insert', pos, component.i);
            result.push(pos += component.i.length);
          } else {
            // delete
            result.push(this.emit('delete', pos, component.d));
          }
        }
        return result;
      })();
    });
  }
};
          // We don't increment pos, because the position
          // specified is after the delete has happened.