The other answers were incomplete for me. I started from @Vladimir Novopashin answer and modified it. Here are the things, that I needed and bug I found:
- Support for file
- Support for array
- Bug: File inside complex object needs to be added with
.prop instead of [prop]. For example, formData.append('photos[0][file]', file) didn't work on google chrome, while
formData.append('photos[0].file', file) worked
- Ignore some properties in my object
The following code should work on IE11 and evergreen browsers.
function objectToFormData(obj, rootName, ignoreList) {
var formData = new FormData();
function appendFormData(data, root) {
if (!ignore(root)) {
root = root || '';
if (data instanceof File) {
formData.append(root, data);
} else if (Array.isArray(data)) {
for (var i = 0; i < data.length; i++) {
appendFormData(data[i], root + '[' + i + ']');
}
} else if (typeof data === 'object' && data) {
for (var key in data) {
if (data.hasOwnProperty(key)) {
if (root === '') {
appendFormData(data[key], key);
} else {
appendFormData(data[key], root + '.' + key);
}
}
}
} else {
if (data !== null && data !== undefined) {
formData.append(root, data);
}
}
}
}
function ignore(root){
return Array.isArray(ignoreList)
&& ignoreList.some(function(x) { return x === root; });
}
appendFormData(obj, rootName);
return formData;
}
