source/lib/cell/index.js
function cellAccessor(row1, col1, row2, col2, isMerged) {
    let theseCells = new cellBlock();
    theseCells.ws = this;

    row2 = row2 ? row2 : row1;
    col2 = col2 ? col2 : col1;

    if (row2 > this.lastUsedRow) {
        this.lastUsedRow = row2;
    }

    if (col2 > this.lastUsedCol) {
        this.lastUsedCol = col2;
    }

    for (let r = row1; r <= row2; r++) {
        for (let c = col1; c <= col2; c++) {
            let ref = `${utils.getExcelAlpha(c)}${r}`;
            if (!this.cells[ref]) {
                this.cells[ref] = new Cell(r, c);
            }
            if (!this.rows[r]) {
                this.rows[r] = new Row(r, this);
            }
            if (this.rows[r].cellRefs.indexOf(ref) < 0) {
                this.rows[r].cellRefs.push(ref);
            }

            theseCells.cells.push(this.cells[ref]);
            theseCells.excelRefs.push(ref);
        }
    }
    if (isMerged) {
        theseCells.merged = true;
        mergeCells(theseCells);
    }

    return theseCells;
}
function cellAccessor(row1, col1, row2, col2, isMerged) {
    let theseCells = new cellBlock();
    theseCells.ws = this;

    row2 = row2 ? row2 : row1;
    col2 = col2 ? col2 : col1;

    if (row2 > this.lastUsedRow) {
        this.lastUsedRow = row2;
    }

    if (col2 > this.lastUsedCol) {
        this.lastUsedCol = col2;
    }

    for (let r = row1; r <= row2; r++) {
        for (let c = col1; c <= col2; c++) {
            let ref = `${utils.getExcelAlpha(c)}${r}`;
            if (!this.cells[ref]) {
                this.cells[ref] = new Cell(r, c);
            }
            if (!this.rows[r]) {
                this.rows[r] = new Row(r, this);
            }
            if (this.rows[r].cellRefs.indexOf(ref) < 0) {
                this.rows[r].cellRefs.push(ref);
            }

            theseCells.cells.push(this.cells[ref]);
            theseCells.excelRefs.push(ref);
        }
    }
    if (isMerged) {
        theseCells.merged = true;
        mergeCells(theseCells);
    }

    return theseCells;
}
Module repesenting a Cell Accessor
@alias Worksheet.cell
@namespace
@func Worksheet.cell
@desc Access a range of cells in order to manipulate values
@param {Number} row1 Row of top left cell
@param {Number} col1 Column of top left cell
@param {Number} row2 Row of bottom right cell (optional)
@param {Number} col2 Column of bottom right cell (optional)
@param {Boolean} isMerged Merged the cell range into a single cell
@returns {cellBlock}