var originalModel = monaco.editor.createModel("just some text\n\nHello World\n\nSome more text", "plaintext");
var modifiedModel = monaco.editor.createModel("just some Text\n\nHello World\n\nSome more changes", "plaintext");

var editor = monaco.editor.createDiffEditor(document.getElementById("container"), { modifiedCodeLens: true });
editor.setModel({
	original: originalModel,
    modified: modifiedModel,
});

var commandId = editor.addCommand(0, function () {
    alert('code lens is working!');
}, '');

monaco.languages.registerCodeLensProvider('plaintext', {
    provideCodeLenses: function (model, token) {
        return {
            lenses: [
                {
                    range: {
                        startLineNumber: 1,
                        startColumn: 1,
                        endLineNumber: 2,
                        endColumn: 1
                    },
                    id: "First Line",
                    command: {
                        id: commandId,
                        title: "First Line"
                    }
                }
            ]
        };
    },
    resolveCodeLens: function (model, codeLens, token) {
        return codeLens;
    }
});