xlsx-injector

This module allows injection of values into an XLSX template with styling using angular-styled tags {{}}

It is heavily based on Martin Aspeli's (https://github.com/optilude) xlsx-template , but is modified in an opinionated fashion to work better in certain workflows. If you are looking for more flexibility and/or control, you may be better off using the xlsx-template (https://github.com/optilude/xlsx-template) library instead.

What It Does

This module allows you to use any existing xlsx file and inject values into it without losing any styling information.

Why Would You Use This

If you're looking to create dynamic Excel based reports, this tool will allow you to do that.

How To Install This

npm install xlsx-injector

How To Use

Basic Workflow

• Create a template file as an .xlsx
• Style it up, and use placeholders
• Using the xlsx-injector, load the template xlsx
• Inject substitution values via a Javascript object
• Save the file as a new .xlsx

Placeholders

Placeholders are inserted in cells in a spreadsheet. It does not matter how those cells are formatted, so e.g. it is OK to insert a placeholder (which is text content) into a cell formatted as a number or currecy or date, if you expect the placeholder to resolve to a number or currency or date.

This module uses {{ }} placeholders, which should be familiar to users of Handlebars or Angular.

Scalars

Simple placholders take the format {{name}}. Here, name is the name of a key in the placeholders map. The value of this placholder here should be a scalar, i.e. not an array or object. The placeholder may appear on its own in a cell, or as part of a text string. For example:

| Extracted on: | {{extractDate}} |

might result in (depending on date formatting in the second cell):

| Extracted on: | Jun-01-2013 |

Here, extractDate may be a date and the second cell may be formatted as a number.

Columns

You can use arrays as placeholder values to indicate that the placeholder cell is to be replicated across columns. In this case, the placeholder cannot appear inside a text string - it must be the only thing in its cell. For example, if the placehodler value dates is an array of dates:

| {{dates}} |

might result in:

| Jun-01-2013 | Jun-02-2013 | Jun-03-2013 |

Tables

Finally, you can build tables made up of multiple rows. In this case, each placeholder should be prefixed by table: and contain both the name of the placeholder variable (a list of objects) and a key (in each object in the list). For example:

| Name                  | Age                  |
| {{table:people.name}} | {{table:people.age}} |

If the replacement value under people is an array of objects, and each of those objects have keys name and age, you may end up with something like:

| Name        | Age |
| John Smith  | 20  |
| Bob Johnson | 22  |

If a particular value is an array, then it will be repeated accross columns as above.

Generating reports

To make this magic happen, you need some code like this:

(Coffeescript example)

  XlsxInjector = require('xlsx-injector')

  templatePath = "./path/to/template.xlsx"
  outputPath = "./path/to/output_file.xlsx"

  # Object containing attributes that match the placeholder tokens in the template
  values = 
    extractDate: new Date()
    dates: [new Date("2013-06-01"), new Date("2013-06-02"), new Date("2013-06-03")]
    people: [
        {name: "John Smith", age: 20}
        {name: "Bob Johnson", age: 22}
    ]

  # Open a workbook
  workbook = new XlsxInjector(templatePath)
  sheetNumber = 1
  workbook.substitute sheetNumber, values
  # Save the workbook
  workbook.writeFile(outputPath)

Caveats

• Only .xlsx is supported
• Column (array) and table (array-of-objects) insertions cause rows and cells to be inserted or removed. When this happens, only a limited number of adjustments are made:
  • Merged cells and named cells/ranges to the right of cells where insertions or deletions are made are moved right or left, appropriately. This may not work well if cells are merged across rows, unless all rows have the same number of insertions.
  • Merged cells, named tables or named cells/ranges below rows where further rows are inserted are moved down. Formulae are not adjusted.
• Placeholders only work in simple cells and tables, pivot tables or other such things.

Things At Risk of Changing

• The table: prefix is subject to change in a newer version

Changelog

0.0.3

• Remove unused sugar dependency

0.0.2

• No significant changes

0.0.1

• Initial release
• Convert original code to Coffeescript
• Add Windows compatibility
• Purge elements on cells with #VALUE! to allow for auto-calculation of formula cells when the output workbook is loaded in Excel or Office 365.
• Bake in XLSX load and write functions

Attributions

Functionality not in the original xlsx-template is Copyright (c) 2015, Assign It To Us Technologies

Original xlsx-template code is Copyright (c) 2013 Martin Aspeli

If you are looking for the xlsx-template npm, it is available here: https://github.com/optilude/xlsx-template