After Effects Expression : Reveal text (TypeOn + blinking cursor)

After Effects Expression : Reveal text (TypeOn + blinking cursor)

//put this expression for the 'Source Text' value on your text layer, and add 4 markers on the layer : 'cursorStart', 'textStart', 'textStop', 'cursorStop'

cursor="|";
cursorBlink = 1; //seconds
txt = value;
timeIn = thisLayer.inPoint; //seconds
txtSize = text.sourceText.length;

animateText = true;
showCursor = true;

//check if required markers exists
try{
  textStart = marker.key('textStart').time;
  textStop = marker.key('textStop').time;
}catch(e){
  AnimateText = false;
}

//check if required markers exists
try{
  cursorStart = marker.key('cursorStart').time;
  cursorStop = marker.key('cursorStop').time;
}catch(e){
  showCursor = false;
}

if (animateText){
  duration = textStop - textStart; //type-on duration in seconds
  txtIdx = linear(time, textStart, textStop, 0, txtSize);
  txt = substr(0,txtIdx)
}

if (showCursor){
  F = Math.round( (time + cursorStart) % cursorBlink );

  if ( (time > cursorStart) && (time < cursorStop) &&  (F==1) ) {
    txt += cursor;
  }

}

txt;

...Or with a slider 'txtComplete' (0 to 100 percent) that you can use to animate the text progression :

txt = value;
timeIn = thisLayer.inPoint; //seconds
txtSize = text.sourceText.length;
cursor="|";
cursorBlink = 1; //seconds
txtComplete = 100; //percents - add a slider 'txtComplete' on your layer to animate this value

animateText = true;
showCursor = true;

//check if required markers exists
try{
  txtComplete = effect("txtComplete")("Slider");
}catch(e){
  AnimateText = false;
}

//check if required markers exists
try{
  cursorStart = marker.key('cursorStart').time;
  cursorStop = marker.key('cursorStop').time;
}catch(e){
  showCursor = false;
}


if (animateText){
  txtIdx = txtSize / 100 * txtComplete;
  txt = substr(0,txtIdx)
}

if (showCursor){
  F = Math.round( (time + cursorStart) % cursorBlink );

  if ( (time > cursorStart) && (time < cursorStop) &&  (F==1) ) {
    txt += cursor;
  }

}

txt;