How to use the quill.Delta function in quill

function test_DeltaDiff() {
    const a = new Delta().insert('Hello');
    const b = new Delta().insert('Hello!');

    const diff = a.diff(b);  // { ops: [{ retain: 5 }, { insert: '!' }] }
                           // a.compose(diff) == b
    const diff2 = a.diff(b, 0);  // { ops: [{ retain: 5 }, { insert: '!' }] }
                               // a.compose(diff) == b
}

function test_DeltaCompose() {
    const a = new Delta().insert('abc');
    const b = new Delta().retain(1).delete(1);

    const composed = a.compose(b);  // composed == new Delta().insert('ac');
}

function test_DeltaCompose() {
    const a = new Delta().insert('abc');
    const b = new Delta().retain(1).delete(1);

    const composed = a.compose(b);  // composed == new Delta().insert('ac');
}

function test_DeltatransformPosition() {
    const delta = new Delta().retain(5).insert('a');
    const n1: number = delta.transformPosition(4); // 4
    const n2: number = delta.transformPosition(5); // 6
    const n3: number = delta.transformPosition(5, true);
    const n4: number = delta.transformPosition(5, false);
}

function test_DeltaTransform() {
    const a = new Delta().insert('a');
    const b = new Delta().insert('b').retain(5).insert('c');

    const d1: DeltaStatic = a.transform(b, true);  // new Delta().retain(1).insert('b').retain(5).insert('c');
    const d2: DeltaStatic = a.transform(b, false); // new Delta().insert('b').retain(6).insert('c');
    const n1: number = a.transform(5);
    const n2: number = a.transform(5, true);
    const n3: number = a.transform(5, false);
}

function test_DeltaForEach() {
    const delta = new Delta();
    delta.forEach((op: any) => console.log(op));
}

function test_DeltaChaining() {
    const delta = new Delta()
        .insert('Hello', { bold: true })
        .insert('World')
        .delete(5)
        .retain(5)
        .retain(5, { color: '#0c6' });
}

function test_setDeltaContents() {
    const quillEditor = new Quill('#editor');
    quillEditor.setContents(new Delta({ ops: [
        { insert: 'Hello ' },
        { insert: 'World!', attributes: { bold: true } },
        { insert: '\n' }
    ]}));
}

function test_DeltaFilter() {
    const delta = new Delta().insert('Hello', { bold: true })
        .insert({ image: 'https://octodex.github.com/images/labtocat.png' })
        .insert('World!');

    const text = delta
      .filter((op: any) => typeof op.insert === 'string')
      .map((op: any) => op.insert)
      .join('');
}

createDeltaSegmentStateMachineHasLearnt(value: boolean, index: number, segment: Segment,
                                          length: number = 1): DeltaStatic {
    const format: FormatMachine = {};
    if (segment.state.status != null) {
      format.status = segment.state.status.toString();
    }
    format.machineHasLearnt = value.toString();
    const formats: StringMap = { state: format };
    return new Delta().retain(index).retain(length, formats);
  }