Keybore

Create every integer using only + and -

HTML

<p>
Rules:
</p>
<ol>
<li>Start at 0.</li>
<li>Each consecutive +/- increases/decreases the number by an amount increasing by 1.</li>
<li>For example, + is 1, ++ is 3, +++ is 6, ++++ is 10, +++++ is 15, +++++- is 14.</li>
<li>All other characters are ignored.</li>
</ol>
Input code: <textarea id=input oninput=process() style="width:100%">++++++++++++++++++++++++++++++++++++</textarea>
<br /><br />
Output: <input id=output readonly style="background:#B4B4B4; border:0px; width:100%" value="666" />

Babel + JSX

window.process=(code=document.getElementById("input").value)=>{
	var code = code.replace(/[^+-]/g,"")
  var result = 0
  var counter = 0
  var current = ""
  for(var ch of code){
  	if(ch != current){
    	if(current == '+'){
      	result += counter*(counter+1)/2
      }else{
      	result -= counter*(counter+1)/2
      }
    	counter = 1
      current = ch
    }else{
    	counter++
    }
  }
  if(current == '+'){
  	result += counter*(counter+1)/2
  }else{
  	result -= counter*(counter+1)/2
	}
  document.getElementById("output").value = result
}