file_iterator.ts

export interface Field {
  contentType?: string;
  filename?: string;
  name: string;
  value: string | Uint8Array;
}

export const boundary = Math.random().toString(16).substring(2);

export async function* fileIterator(fields: Field[]) {
  for (let i = 0; i < fields.length; i++) {
    const field = fields[i];
    let str = `Content-Disposition:form-data;name=${field.name}`;
    if (field.filename !== undefined) {
      str += `;filename=${field.filename}`;
    }
    if (field.contentType !== undefined) {
      str += `;Content-Type:${field.contentType}`;
    }
    yield `\n--${boundary}\n${str}\n\n`;
    yield field.value;
  }
  yield `\n--${boundary}--`;
}