//String
indexOf() // gets index of character
split("delimiter") // Split a string into an array of substrings:
length //Return the number of characters in a string
match // Search a string for "ain":
slice() // remove characters from front
​
// Arrays 
splice() // add elementsto array
toString() // convert to string 
​
//REGEX
\t // tab
\n // line
\r // carriage return
\s // whitespace
​
​
Ref: https://www.w3schools.com/jsref/jsref_replace.asp

// Selection
var proj = app.project;
var myComp = app.project.activeItem; // or use "comp"
var myLayers = myComp.selectedLayers;
​
​
// Setting values 
~.property("Position").setValue([120,120]);
​
// making guide layers
.guideLayer = true;
​
// adding expressions
var exp = "string of expression";
~.transform.position.expression =exp;

// Using ID number
var inMenuID = 2000;
app.executeCommand(inMenuID);
​
​
// Using name
app.executeCommand(app.findMenuCommandId("New Project"));

//solid
app.project.item(index).layers.addSolid(color, name, width, height, pixelAspect[, duration])
​
//null
myNull = app.project.activeItem.layers.addNull(); 
​
​

// Add Adjustment Layer with Effect.jsx
try{
    var adjLayer = app.project.activeItem.layers.addSolid([0,0,0], "Adjustment Layer", app.project.activeItem.width, app.project.activeItem.height, app.project.activeItem.pixelAspect, app.project.activeItem.duration);
    adjLayer.adjustmentLayer = true;
    adjLayer.effect.addProperty("Curves"); 
    }
catch (e) {
    alert (e);
    }

app.project.activeItem.layers.addText('sourceText')
myText.property("Source Text").expression = " thisComp.name + \" (\" + (1 + (time/thisComp.frameDuration)) + \")\"  "; //add expression
myText.property("Position").setValue([172, 644]); //set position to lower right corner
​
//using an array
var content = ['text','text','text'] // read content
for(var i=0; i < content.length; i++){
    app.project.activeItem.layers.addText(content[i]);
}
​

myComp = app.project.activeItem;
myColor = [0,128,255]; // How to set hex code though? Attached to a global fill?
​
// Create shape layer
var myShapeLayer = myComp.layers.addShape();
myShapeLayer.name = ("minRect");
​
// Create shape layer & shape (Ellipse, Rect,)
var shapeGroup = myShapeLayer.property("Contents").addProperty("ADBE Vector Group");
var myRect = shapeGroup.property("Contents").addProperty("ADBE Vector Shape - Rect"); //
myRect.property("Size").setValue([300,100]);
​
// Create stroke properties
var myStroke = shapeGroup.property("Contents").addProperty("ADBE Vector Graphic - Stroke");
myStroke.property("Color").setValue(myColor);
myStroke.property("Opacity").setValue([100]);
myStroke.property("Stroke Width").setValue([2]);
​
​
// Create fill
var myFill = shapeGroup.property("Contents").addProperty("ADBE Vector Graphic - Fill");
myFill.property("Color").setValue(myColor);
myFill.property("Opacity").setValue([100]);
var myRepeater = shapeGroup.property("Contents").addProperty("ADBE Vector Filter - Repeater");
​
// Source: https://forums.creativecow.net/docs/forums/post.php?forumid=227&postid=28156&univpostid=28156&pview=t

// Source: https://stackoverflow.com/questions/17665920/open-web-page-in-after-effects-with-extendscript
​
// checking that the script can access the network:
​
if (app.preferences.getPrefAsLong("Main Pref Section", "Pref_SCRIPTING_FILE_NETWORK_SECURITY") != 1) {
    alert("Please tick the \"Allow Scripts to Write Files and Access Network\" checkbox if Preferences > General");
​
    // Then open Preferences > General to let people tick the checkbox
    app.executeCommand(2359);
​
    // Here you should check again if they ticked it, and choose to continue or stop ...
}
// checking of the OS:
​
var os = system.osName;
if (!os.length) {
    // I never remember which one is available, but I think $.os always is, you'll have to check
    os = $.os;
}
app_os = (os.indexOf("Win") != -1) ? "Win" : "Mac"
​
//os-dependent system calls:
​
var url = "http://aescripts.com";
​
if (app_os == "Win") {
    system.callSystem("explorer " + url);
} else {
    system.callSystem("open " + url);
}

for (var i=0; i<proj.selection.length; i++)
{
    if (proj.selection[i] instanceof CompItem)
        comps[comps.length] = proj.selection[i];
}

var myLayer = app.project.activeItem.layer(1);
var hasEffect = false;
​
for (var i = 1; i <= myLayer.property("Effects").numProperties; i++) {
    if (myLayer.property("Effects").property(i).matchName == "ADBE Tile") {
        alert("It does!");
        hasEffect = true;
        break;
    }
}
​
if (!hasEffect) {
    myLayer.property("Effects").addProperty("ADBE Tile");
}

IndexOf is a string function and doesn't work with arrays anywhere.
​
​
//Source: https://forums.creativecow.net/docs/forums/post.php?forumid=227&postid=37977&univpostid=37977&pview=t

​

​
//Distributes layers in 2D space within comp size
var thisComp = app.project.activeItem;
var myLayers = thisComp.selectedLayers;
var x = thisComp.width;
var y = thisComp.height;
var randX,randY;
​
function getRndNum(min, max) {
  return Math.random() * (max - min) + min;
}
for(i=0; i<myLayers.length; i++){
  randX = getRndNum(0,x);
  randY = getRndNum(0,y);
  myLayers[i].property("Position").setValue([randX,randY,0]);
  // myLayers[i].property("Position").setValue([x,y])
​
}
​

/* Changes the background color for the active comp to white. 
Can be customized to any color you'd like by simply changing the [1,1,1] value to reflect the appropriate RGB values...
​
Example colors:
[0,0,0] = Black
[0.5,0.5,0.5] = Grey
*/
​
app.project.activeItem.bgColor=[1,1,1];

{
	var activeItem = app.project.activeItem;
​
	if (activeItem == null || !(activeItem instanceof CompItem)) {
		alert("Select a comp before running this script");
	} else {
		if (activeItem.selectedLayers.length < 1) {
			alert("Select a solid layer before running this script");
		} else {
			solidLayer = activeItem.selectedLayers[0];
			solidLayer.source.mainSource.color = [1,1,1];
			alert("Changed solid's color to white.");
		}
	}
}

myComp = app.project.activeItem
var bg = myComp.bgColor;
var n =0 ;
​
var baseColor = [0,0,0];
var col_1 = [1,1,1];
var col_2 = [.5,.5,.5];
​
​
if(bg[0]==0&&bg[1]==0&&bg[2]==0) {n=1} // black to white
if(bg[0]==1&&bg[1]==1&&bg[2]==1) {n=2} // white to grey
if(bg[0]==.5&&bg[1]==.5&&bg[2]==.5) {n=3} // grey to black
​
​
switch(n){
  case 0:
    app.project.activeItem.bgColor = baseColor;
  break;
​
  case 1:
    app.project.activeItem.bgColor = col_1;
    break;
​
	case 2:
    app.project.activeItem.bgColor = col_2;
    break;
​
	case 3:
    app.project.activeItem.bgColor = baseColor;
    break;
}
​