get/set caret position in contentEditable or textarea/input element(JavaScript)

caret.js

/**
 * @file get/set caret position and insert text
 * @author islishude
 * @license MIT
 */
export class Caret {
    /**
     * get/set caret position
     * @param {HTMLColletion} target 
     */
    constructor(target) {
        this.isContentEditable = target && target.contentEditable
        this.target = target
    }
    /**
     * get caret position
     * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/Range}
     * @returns {number}
     */
    getPos() {
        // for contentedit field
        if (this.isContentEditable) {
            this.target.focus()
            let _range = document.getSelection().getRangeAt(0)
            let range = _range.cloneRange()
            range.selectNodeContents(this.target)
            range.setEnd(_rang.endContainer, _range.endOffset)
            return range.toString().length;
        }
        // for texterea/input element
        return this.target.selectionStart
    }

    /**
     * set caret position
     * @param {number} pos - caret position
     */
    setPos(pos) {
        // for contentedit field
        if (this.isContentEditable) {
            this.target.focus()
            document.getSelection().collapse(this.target, pos)
            return
        }
        this.target.setSelectionRange(pos, pos)
    }
}

/**
 * insert text or orther to editor
 * @see https://developer.mozilla.org/en-US/docs/Web/API/Document/execCommand
 * @module Editor
 */
export class Editor {
    constructor() {

    }
    /**
     * @param {string} content - your insert text
     * @returns {boolean} 
     */
    insertText(content) {
        document.execCommand('insertText', false, content)
    }
}

Hey! It seems a small mistake at 27 line (_rang)