FileReader extension type

The FileReader interface lets web applications asynchronously read the contents of files (or raw data buffers) stored on the user's computer, using File or Blob objects to specify the file or data to read.

File objects may be obtained from a FileList object returned as a result of a user selecting files using the input element, or from a drag and drop operation's DataTransfer object.

FileReader can only access the contents of files that the user has explicitly selected, either using an HTML <input type="file"> element or by drag and drop. It cannot be used to read a file by pathname from the user's file system. To read files on the client's file system by pathname, use the File System Access API. To read server-side files, use fetch, with CORS permission if reading cross-origin.

API documentation sourced from MDN Web Docs.

on

JSObject

Implemented types

Available extensions

Constructors

FileReader(): factory

Properties

asString → String: Available on JSAny, provided by the JSAnyExtension extension

no setter
asString → String?: Available on JSAny?, provided by the JSAnyNullableExtension extension

no setter
entries → Iterable<MapEntry<String, dynamic>>: Available on JSObject, provided by the JSObjectExtension extension

no setter
error → DOMException?: The error read-only property of the FileReader interface returns the error that occurred while reading the file.
no setter
hashCode → int: The hash code for this object.
no setterinherited
isDefinedAndNotNull → bool: Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter
isElement → bool: Available on JSObject?, provided by the JSObjectWebExtension extension

no setter
isHTMLElement → bool: Available on JSObject?, provided by the JSObjectWebExtension extension

no setter
isNode → bool: Available on JSObject?, provided by the JSObjectWebExtension extension

no setter
isNull → bool: Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension
Whether this value corresponds to JavaScript null.
no setter
isTruthy → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of !!this in JavaScript.
no setter
isUndefined → bool: Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension
Whether this value corresponds to JavaScript undefined.
no setter
isUndefinedOrNull → bool: Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter
keys → Iterable<String>: Available on JSObject, provided by the JSObjectExtension extension

no setter
not → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of !this in JavaScript.
no setter
onabort ↔ EventHandler?: getter/setter pair
onAbort → Stream<ProgressEvent>: Available on FileReader, provided by the FileReaderExtension extension

no setter
onerror ↔ EventHandler?: getter/setter pair
onError → Stream<ProgressEvent>: Available on FileReader, provided by the FileReaderExtension extension

no setter
onload ↔ EventHandler?: getter/setter pair
onLoad → Stream<ProgressEvent>: Available on FileReader, provided by the FileReaderExtension extension

no setter
onloadend ↔ EventHandler?: getter/setter pair
onLoadEnd → Stream<ProgressEvent>: Available on FileReader, provided by the FileReaderEventGEtters extension

no setter
onloadstart ↔ EventHandler?: getter/setter pair
onLoadStart → Stream<ProgressEvent>: Available on FileReader, provided by the FileReaderExtension extension

no setter
onprogress ↔ EventHandler?: getter/setter pair
readyState → int: The readyState read-only property of the FileReader interface provides the current state of the reading operation. This will be one of the states: EMPTY, LOADING, or DONE.
no setter
result → JSAny?: The result read-only property of the FileReader interface returns the file's contents. This property is only valid after the read operation is complete, and the format of the data depends on which of the methods was used to initiate the read operation.
no setter
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited

Methods

abort() → void: The abort() method of the FileReader interface aborts the read operation. Upon return, the FileReader.readyState will be DONE.
add(JSAny? any) → JSAny: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this + any in JavaScript.
addEventListener(String type, EventListener? callback, [JSAny options]) → void: The addEventListener() method of the EventTarget interface sets up a function that will be called whenever the specified event is delivered to the target.
inherited
and(JSAny? any) → JSAny?: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this && any in JavaScript.
as<T extends JSObject>() → T?: Available on JSObject, provided by the JSObjectExtension extension
callMethod<R extends JSAny?>(JSAny method, [JSAny? arg1, JSAny? arg2, JSAny? arg3, JSAny? arg4]) → R: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Calls method on this JSObject with up to four arguments.
callMethodVarArgs<R extends JSAny?>(JSAny method, [List<JSAny?>? arguments]) → R: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Calls method on this JSObject with a variable number of arguments.
dartify() → Object?: Available on JSAny?, provided by the JSAnyUtilityExtension extension
Converts a JavaScript JSON-like value to the Dart equivalent if possible.
delete(JSAny property) → JSBoolean: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Deletes the property with key property from this JSObject.
dispatchEvent(Event event) → bool: The dispatchEvent() method of the EventTarget sends an Event to the object, (synchronously) invoking the affected event listeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) also apply to events dispatched manually with dispatchEvent().
inherited
divide(JSAny? any) → JSAny: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this / any in JavaScript.
equals(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this == any in JavaScript.
exponentiate(JSAny? any) → JSAny: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this ** any in JavaScript.
get(String key) → Object?: Available on JSObject, provided by the JSObjectExtension extension
getProperty<R extends JSAny?>(JSAny property) → R: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
The value of the property key property of this JSObject.
greaterThan(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this > any in JavaScript.
greaterThanOrEqualTo(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this >= any in JavaScript.
has(String property) → bool: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Shorthand helper for hasProperty to check whether this JSObject contains the property key property, but takes and returns a Dart value.
hasProperty(JSAny property) → JSBoolean: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Whether or not this JSObject contains the property key property.
instanceof(JSFunction constructor) → bool: Available on JSAny?, provided by the JSAnyUtilityExtension extension
Whether this JSAny? is an instanceof constructor.
instanceOfString(String constructorName) → bool: Available on JSAny?, provided by the JSAnyUtilityExtension extension
Whether this JSAny? is an instanceof the constructor that is defined by constructorName, which is looked up in the globalContext.
isA<T extends JSAny?>() → bool: Available on JSAny?, provided by the JSAnyUtilityExtension extension
Whether this JSAny? is an instance of the JavaScript type that is declared by T.
lessThan(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this < any in JavaScript.
lessThanOrEqualTo(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this <= any in JavaScript.
modulo(JSAny? any) → JSAny: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this % any in JavaScript.
multiply(JSAny? any) → JSAny: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this * any in JavaScript.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
notEquals(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this != any in JavaScript.
or(JSAny? any) → JSAny?: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this || any in JavaScript.
put(Object key, Object? value) → void: Available on JSObject, provided by the JSObjectExtension extension
readAsArrayBuffer(Blob blob) → void: The readAsArrayBuffer() method of the FileReader interface is used to start reading the contents of a specified Blob or File. When the read operation is finished, the FileReader.readyState property becomes DONE, and the FileReader.loadend_event event is triggered. At that time, the FileReader.result property contains an ArrayBuffer representing the file's data.
readAsBinaryString(Blob blob) → void: Note: This method is deprecated in favor of FileReader.readAsArrayBuffer.
readAsDataURL(Blob blob) → void: The readAsDataURL() method of the FileReader interface is used to read the contents of the specified Blob or File. When the read operation is finished, the FileReader.readyState property becomes DONE, and the FileReader.loadend_event event is triggered. At that time, the FileReader.result attribute contains the data as a data: URL representing the file's data as a base64 encoded string.
readAsText(Blob blob, [String encoding]) → void: The readAsText() method of the FileReader interface is used to read the contents of the specified Blob or File. When the read operation is complete, the FileReader.readyState property is changed to DONE, the FileReader.loadend_event event is triggered, and the FileReader.result property contains the contents of the file as a text string.
removeEventListener(String type, EventListener? callback, [JSAny options]) → void: The removeEventListener() method of the EventTarget interface removes an event listener previously registered with EventTarget.addEventListener from the target. The event listener to be removed is identified using a combination of the event type, the event listener function itself, and various optional options that may affect the matching process; see Matching event listeners for removal.
inherited
setProperty(JSAny property, JSAny? value) → void: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Write the value of property key property of this JSObject.
strictEquals(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this === any in JavaScript.
strictNotEquals(JSAny? any) → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this !== any in JavaScript.
subtract(JSAny? any) → JSAny: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this - any in JavaScript.
toMap() → Map<String, dynamic>: Available on JSObject, provided by the JSObjectExtension extension
toString() → String: A string representation of this object.
inherited
typeofEquals(String typeString) → bool: Available on JSAny?, provided by the JSAnyUtilityExtension extension
Whether the result of typeof on this JSAny? is typeString.
unsignedRightShift(JSAny? any) → JSNumber: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of this >>> any in JavaScript.

Operators

operator ==(Object other) → bool: The equality operator.
inherited
operator [](String property) → JSAny?: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Shorthand helper for getProperty to get the value of the property key property of this JSObject, but takes a Dart value.
operator []=(String property, JSAny? value) → void: Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension
Shorthand helper for setProperty to write the value of the property key property of this JSObject, but takes a Dart value.

Constants

DONE → const int
EMPTY → const int
LOADING → const int