Various snippets for selecting Photoshop channels

Select Channels.jsx

/* 
NOTES:
The channels array is zero indexed, channels[0] is at the top/head of the channels panel
The top-level "primary/composite" of the ChannelType.COMPONENT is not included in the individual layer count
*/


// Save the current active channels
var savedChannelState = app.activeDocument.activeChannels;

/***************************************************************************************************/

// Select/target/activate the top/first channel
selectFirstChannel();

function selectFirstChannel() {
    var theChannels = new Array(app.activeDocument.channels[0]);
    app.activeDocument.activeChannels = theChannels;
    alert("Top/first channel selected");
};

/***************************************************************************************************/

// Select/target/activate the 2nd and 4th channels
selectTwoChannels();

function selectTwoChannels() {
    var theChannels = new Array(app.activeDocument.channels[1], app.activeDocument.channels[3]);
    app.activeDocument.activeChannels = theChannels;
    alert("2nd & 4th channels selected");
};

/***************************************************************************************************/

// Select/target/activate the bottom/last channel
selectLastChannel();

function selectLastChannel() {
    // var theChannels = new Array(app.activeDocument.channels[app.activeDocument.channels.length - 1]);
    var lastChannel = app.activeDocument.channels.length - 1;
    var theChannels = new Array(app.activeDocument.channels[lastChannel]);
    app.activeDocument.activeChannels = theChannels;
    alert("Bottom/last channel selected");
};

/***************************************************************************************************/

// Select/target/activate the componentChannels
app.activeDocument.activeChannels = app.activeDocument.componentChannels;
alert("componentChannels selected");

/***************************************************************************************************/

// Select/target/activate channel by name
selectChannelByName("Spot Color 1");

function selectChannelByName(channelName) {
    var channelByName = new Array(app.activeDocument.channels[channelName]);
    app.activeDocument.activeChannels = channelByName;
    alert(channelByName + " selected");
};

/***************************************************************************************************/

selectAllSpotChannels();

function selectAllSpotChannels() {
    var totCha = app.activeDocument.channels.length;
    var actCha = new Array();
    for (var i = (totCha - 1); i >= 0; i--) {
        if (app.activeDocument.channels[i].kind === ChannelType.SPOTCOLOR) {
            actCha.push(app.activeDocument.channels[i]);
        }
    }
    app.activeDocument.activeChannels = actCha;
    alert("All spot channels selected");
};

/***************************************************************************************************/

selectAllSELECTEDAREAalphaChannels();

function selectAllSELECTEDAREAalphaChannels() {
    var totCha = app.activeDocument.channels.length;
    var actCha = new Array();
    for (var i = (totCha - 1); i >= 0; i--) {
        if (app.activeDocument.channels[i].kind === ChannelType.SELECTEDAREA) {
            actCha.push(app.activeDocument.channels[i]);
        }
    }
    app.activeDocument.activeChannels = actCha;
    alert("All SELECTEDAREA alpha channels selected");
};

/***************************************************************************************************/

selectAllMASKEDAREAalphaChannels();

function selectAllMASKEDAREAalphaChannels() {
    var totCha = app.activeDocument.channels.length;
    var actCha = new Array();
    for (var i = (totCha - 1); i >= 0; i--) {
        if (app.activeDocument.channels[i].kind === ChannelType.MASKEDAREA) {
            actCha.push(app.activeDocument.channels[i]);
        }
    }
    app.activeDocument.activeChannels = actCha;
    alert("All MASKEDAREA alpha channels selected");
};

/***************************************************************************************************/

selectAllalphaChannels();

function selectAllalphaChannels() {
    var totCha = app.activeDocument.channels.length;
    var actCha = new Array();
    for (var i = (totCha - 1); i >= 0; i--) {
        if (app.activeDocument.channels[i].kind === ChannelType.SELECTEDAREA || app.activeDocument.channels[i].kind === ChannelType.MASKEDAREA) {
            actCha.push(app.activeDocument.channels[i]);
        }
    }
    app.activeDocument.activeChannels = actCha;
    alert("All alpha channels selected");
};

/***************************************************************************************************/

// Select/target/activate all channels
selectAllChannels();

function selectAllChannels() {
    var totCha = app.activeDocument.channels.length;
    var actCha = new Array();
    for (var i = (totCha - 1); i >= 0; i--) {
        actCha.push(app.activeDocument.channels[i]);
    }
    app.activeDocument.activeChannels = actCha;
    alert("All channels selected");
};

/***************************************************************************************************/

// Restore the saved active channels
app.activeDocument.activeChannels = savedChannelState;