single line or multiline text.jsx

// Test file:
// ====================================
// https://www.dropbox.com/s/dokdemxve0wd6yp/singleline%20or%20multiline%20text%20-%20test.psd?dl=0

// My results: 
// ====================================
// (TRUE) 1. Singleline Point text
// (TRUE) 2. Singleline Paragraph text
// (FALSE) 3. Multiline Point text.Forced linebreak
// (FALSE) 4. Multiline Paragraph text. No forced line breaks.
// (FALSE) 5. Multiline Paragraph text. OVERFLOWING TEXT. No forced line breaks.
// (FALSE) 6. Multiline Paragraph text. Forced linebreaks.
// (FALSE) 7. Multiline Paragraph text. Forced linebreaks. OVERFLOWING TEXT.

var doc = app.activeDocument;
var textGroup = doc.layerSets.getByName('Text');

for ( var i=0; i < textGroup.layers.length; i++ ) {
    doc.activeLayer = textGroup.layers[i];
    $.writeln(  '(' + singleLine( doc.activeLayer ) .toString().toUpperCase() + ') ' + doc.activeLayer.textItem.contents.replace(/\r/g,'') + '\n\n' );
}

function singleLine() {
    
    var doc = app.activeDocument;
    var layer = doc.activeLayer;

    var historyRollback = doc.activeHistoryState;
    var rulerUnits = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.POINTS;

    var height1 = size( layer )[1];
    layer.textItem.noBreak = true;
    layer.textItem.contents = layer.textItem.contents.replace(/\r/g,'');
    var height2 = size( layer )[1];

    var singleline = height1 > height2 ? false : true;
    app.preferences.rulerUnits = rulerUnits;
    doc.activeHistoryState = historyRollback;
    doc.activeLayer = layer;
    
    return singleline;
    
    function size( layer ) {

        var bounds = layer.boundsNoEffects;
        var top = bounds[1].value;
        var right = bounds[2].value;
        var bottom = bounds[3].value;
        var left = bounds[0].value;
        var width = right - left;
        var height = bottom - top;

        return [ width, height ];

    }

}