Cypress.Blob

Cypress automatically includes a Blob library and exposes it as Cypress.Blob.

Use Cypress.Blob to convert base64 strings to Blob objects. Useful for testing uploads.

Syntax

Cypress.Blob.method()

Usage

Correct Usage

Cypress.Blob.method()

Incorrect Usage

cy.Blob.method() // Errors, cannot be chained off 'cy'

Examples

Image Fixture

Using an image fixture for jQuery plugin upload

// programmatically upload the logo
cy.fixture('images/logo.png').as('logo')
cy.get('input[type=file]').then(function ($input) {
  // convert the logo base64 string to a blob
  const blob = Cypress.Blob.base64StringToBlob(this.logo, 'image/png')

  // pass the blob to the fileupload jQuery plugin
  // https://github.com/blueimp/jQuery-File-Upload
  // used in your application's code
  // which initiates a programmatic upload
  $input.fileupload('add', { files: blob })
})

Using an image fixture for upload

// programmatically upload the logo
cy.fixture('images/logo.png').as('logo')
cy.get('input[type=file]').then(function (el) {
  // convert the logo base64 string to a blob
  const blob = Cypress.Blob.base64StringToBlob(this.logo, 'image/png')

  const file = new File([blob], 'images/logo.png', { type: 'image/png' })
  const list = new DataTransfer()

  list.items.add(file)
  const myFileList = list.files

  el[0].files = myFileList
  el[0].dispatchEvent(new Event('change', { bubbles: true }))
})

Getting dataUrl string

Create an `img` element and set its `src` to the `dataUrl`

return Cypress.Blob.imgSrcToDataURL('/assets/img/logo.png').then((dataUrl) => {
  const img = Cypress.$('<img />', { src: dataUrl })

  cy.get('.utility-blob').then(($div) => {
    // append the image
    $div.append(img)
  })
  cy.get('.utility-blob img').click().should('have.attr', 'src', dataUrl)
})

History

Version	Changes
5.0.0	Return type of `arrayBufferToBlob`, `base64StringToBlob`, `binaryStringToBlob`, and `dataURLToBlob` methods changed from `Promise<Blob>` to `Blob`
5.0.0	Added `arrayBufferToBinaryString`, `binaryStringToArrayBuffer` methods.