formdata-to-blob.js•1.3 kB
/*! formdata-polyfill. MIT License. Jimmy Wärting <https://jimmy.warting.se/opensource> */
const escape = (str, filename) =>
(filename ? str : str.replace(/\r?\n|\r/g, '\r\n'))
.replace(/\n/g, '%0A')
.replace(/\r/g, '%0D')
.replace(/"/g, '%22')
/**
* pure function to convert any formData instance to a Blob
* instances synchronous without reading all of the files
*
* @param {FormData|*} formData an instance of a formData Class
* @param {Blob|*} [BlobClass=Blob] the Blob class to use when constructing it
*/
export function formDataToBlob (formData, BlobClass = Blob) {
const boundary = ('----formdata-polyfill-' + Math.random())
const chunks = []
const prefix = `--${boundary}\r\nContent-Disposition: form-data; name="`
for (let [name, value] of formData) {
if (typeof value === 'string') {
chunks.push(prefix + escape(name) + `"\r\n\r\n${value.replace(/\r(?!\n)|(?<!\r)\n/g, '\r\n')}\r\n`)
} else {
chunks.push(
prefix + escape(name) + `"; filename="${escape(value.name, 1)}"\r\n` +
`Content-Type: ${value.type || 'application/octet-stream'}\r\n\r\n`,
value,
'\r\n'
)
}
}
chunks.push(`--${boundary}--`)
return new BlobClass(chunks, {
type: 'multipart/form-data; boundary=' + boundary
})
}