After Effects│指定したコンポ・レイヤー名のチェックボックスにチェックを入れるスクリプト

(function () {
    var COMP_NAME = "PracticeSwitch", LAYER_NAME = "Ctrl", EFFECT_NAME = "Toggle";
    var TARGET = 1; // 1 = ON, 0 = OFF
    if (!app.project || (TARGET !== 0 && TARGET !== 1)) { alert("Use TARGET 0 or 1."); return; }
    var comp = null, layer = null, effect = null, i, matches = 0;
    for (i = 1; i <= app.project.numItems; i++) {
        var item = app.project.item(i);
        if (item instanceof CompItem && item.name === COMP_NAME) { comp = item; matches++; }
    }
    if (matches !== 1) { alert("Use exactly one named composition."); return; }
    matches = 0;
    for (i = 1; i <= comp.numLayers; i++) {
        if (comp.layer(i).name === LAYER_NAME) { layer = comp.layer(i); matches++; }
    }
    if (matches !== 1 || layer.locked) { alert("Use one unlocked named control layer."); return; }
    var effects = layer.property("ADBE Effect Parade"); matches = 0;
    if (effects) {
        for (i = 1; i <= effects.numProperties; i++) {
            if (effects.property(i).name === EFFECT_NAME) { effect = effects.property(i); matches++; }
        }
    }
    if (matches !== 1 || effect.matchName !== "ADBE Checkbox Control") { alert("Use one named Checkbox Control."); return; }
    var checkbox = effect.property("ADBE Checkbox Control-0001");
    if (!checkbox || checkbox.numKeys !== 0 || checkbox.expression !== "") {
        alert("Use a checkbox with no keys or expression."); return;
    }
    app.beginUndoGroup("Set named checkbox");
    try { checkbox.setValue(TARGET); }
    catch (error) { alert("Stopped: " + error.toString() + "\nUndo or reopen your practice copy."); }
    finally { app.endUndoGroup(); }
})();