Layer Color Medium Slateblue

// Layer color Medium Slateblue.js
// Sets the timeline layer colour of selected layers (and all descendants) to Medium Slateblue.

var setColorId = function(nodeId, colorIndex) {
    try { api.set(nodeId, { colorId: colorIndex }); return true; } catch (e) {}
    try { api.set(nodeId, { "attributes.colorId": colorIndex }); return true; } catch (_) {}
    return false;
};

var getChildrenSafe = function(nodeId) {
    try { var kids = api.getChildren(nodeId) || []; return kids.slice(); } catch (_) { return []; }
};

var applyRecursively = function(nodeId, colorIndex) {
    setColorId(nodeId, colorIndex);
    var children = getChildrenSafe(nodeId);
    for (var i = 0; i < children.length; i++) applyRecursively(children[i], colorIndex);
};

var selection = api.getSelection();
if (!selection || !selection.length) {
    console.warn("Select layer(s) to set layer colour to Medium Slateblue.");
} else {
    var COLOR_INDEX = 10;
    for (var i = 0; i < selection.length; i++) applyRecursively(selection[i], COLOR_INDEX);
    console.log("\u2713 Set layer colour to Medium Slateblue for " + selection.length + " root layer(s) and their children.");
}