Original and docs: https://gist.github.com/Sominemo/54db02875a6e8a3710b9bf3ca5b9d789

OnWord.class.min.js

class OnWordListener{constructor(e,s){this.parent=s,this.id=e}get info(){return this.parent.getById(this.id)}unset(){this.parent.unset(this.id)}}class OnWord{constructor(e=!1,s,t=!1,i=!1){this.register=[],this.disabled=!1,this.listener=this.handler.bind(this),document.addEventListener("keypress",this.listener),t&&this.listen(e,s,t,i)}listen(e,s,t=!1,i=!1){let r=this.register.findIndex(s=>s.string===e&&t===s.case&&i===s.debug);return-1===r?this.register.push({string:t?e:e.toLowerCase(),stage:0,callback:[s],case:t,debug:i}):this.register[r].callback.push(s),r=-1===r?this.register.length-1:r,new OnWordListener(r,this)}getById(e){return this.register[e]}handler(e){if(this.disabled)return;const{key:s}=e,t=s.toLowerCase();this.register.forEach(e=>{const i=e.case?s:t;e.string[e.stage]===i?(e.stage++,e.debug&&console.log(`${i} = ${e.string[e.stage-1]}`)):(e.debug&&console.log(`${i} != ${e.string[e.stage]}`),e.stage=0),e.stage>=e.string.length&&(e.stage=0,e.callback.forEach(e=>e()))})}unset(e){this.register.splice(e,1)}disable(e){this.disabled=!0,e&&(document.removeEventListener("keypress",this.listener),this.listener=!1)}enable(){this.disabled=!1,this.listener||(this.listener=this.handler.bind(this),document.addEventListener("keypress",this.listener))}}