FileReader extension type

The FileReader object 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-domain.

on

JSObject

Implemented types

Available extensions

Constructors

FileReader(): factory

Properties

error → DOMException?: no setter
hashCode → int: The hash code for this object.
no setterinherited
isDefinedAndNotNull → bool: Available on JSAny?, provided by the NullableUndefineableJSAnyExtension 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
not → JSBoolean: Available on JSAny?, provided by the JSAnyOperatorExtension extension
The result of !this in JavaScript.
no setter
onabort ↔ EventHandler?: getter/setter pair
onerror ↔ EventHandler?: getter/setter pair
onload ↔ EventHandler?: getter/setter pair
onloadend ↔ EventHandler?: getter/setter pair
onLoadEnd → Stream<ProgressEvent>: Available on FileReader, provided by the FileReaderEventGEtters extension

no setter
onloadstart ↔ EventHandler?: getter/setter pair
onprogress ↔ EventHandler?: getter/setter pair
readyState → int: no setter
result → JSAny?: 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.
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.
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.
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 becomes DONE, and the FileReader/loadend_event is triggered. At that time, the FileReader.result attribute 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 becomes DONE, and the FileReader/loadend_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 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.
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.

Static Properties

DONE → int: no setter
EMPTY → int: no setter
LOADING → int: no setter