Base usage
##1. require
Call require('className') before using the Objective-C class.
require('UIView')
var view = UIView.alloc().init()You can use , to separate multiple class to import them at one time.
require('UIView, UIColor')
var view = UIView.alloc().init()
var red = UIColor.redColor()You can use require() directly:
require('UIView').alloc().init()##2. Invoking method
Invoking class method:
var redColor = UIColor.redColor();Invoking instance method:
var view = UIView.alloc().init();
view.setNeedsLayout();Pass params as you do in Obj-C:
var view = UIView.alloc().init();
var superView = UIView.alloc().init()
superView.addSubview(view)
Getting/Setting properties:
view.setBackgroundColor(redColor);
var bgColor = view.backgroundColor();Use _ to seperate multi-params:
var indexPath = require('NSIndexPath').indexPathForRow_inSection(0, 1);Use __ to represent _ in the original Obj-C method name:
// Obj-C: [JPObject _privateMethod];
JPObject.__privateMethod()##3. Special types
Use hash object to represent CGRect / CGPoint / CGSize / NSRange
// Obj-C
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(20, 20, 100, 100)];
[view setCenter:CGPointMake(10,10)];
[view sizeThatFits:CGSizeMake(100, 100)];
CGFloat x = view.frame.origin.x;
NSRange range = NSMakeRange(0, 1);// JS
var view = UIView.alloc().initWithFrame({x:20, y:20, width:100, height:100})
view.setCenter({x: 10, y: 10})
view.sizeThatFits({width: 100, height:100})
var x = view.frame.x
var range = {location: 0, length: 1}Use String to represent Selector in JS:
//Obj-C
[self performSelector:@selector(viewWillAppear:) withObject:@(YES)];//JS
self.performSelector_withObject("viewWillAppear:", 1)null and undefined will pass as nil in Objective-C, use nsnull to represent NSNull:
//Obj-C
@implemention JPTestObject
+ (BOOL)testNull(NSNull *null) {
return [null isKindOfClass:[NSNull class]]
}
@end//JS
require('JPTestObject').testNull(nsnull) //return 1
require('JPTestObject').testNull(null) //return 0##4. NSArray / NSString / NSDictionary
Use NSArray / NSString / NSDictionary as normal NSObject :
//Obj-C
@implementation JPObject
+ (NSArray *)data
{
return @[[NSMutableString stringWithString:@"JS"]]
}
+ (NSMutableDictionary *)dict
{
return [[NSMutableDictionary alloc] init];
}
@end// JS
require('JPObject')
var ocStr = JPObject.data().objectAtIndex(0)
ocStr.appendString("Patch")
var dict = JPObject.dict()
dict.setObject_forKey(ocStr, 'name')
console.log(dict.objectForKey('name')) //output: JSPatchuse .toJS() to convert NSArray / NSString / NSDictionary to JS type.
// JS
var data = require('JPObject').data().toJS()
//data instanceof Array === true
data.push("Patch")
var dict = JPObject.dict()
dict.setObject_forKey(data.join(''), 'name')
dict = dict.toJS()
console.log(dict['name']) //output: JSPatch##5. Block
Use block(paramTypes, function) to warp JS function when passing JS function as block to Obj-C
// Obj-C
@implementation JPObject
+ (void)request:(void(^)(NSString *content, BOOL success))callback
{
callback(@"I'm content", YES);
}
@end// JS
require('JPObject').request(block("NSString *, BOOL", function(ctn, succ) {
if (succ) log(ctn) //output: I'm content
}))
Just call directly when the block passing from Obj-C to JS:
// Obj-C
@implementation JPObject
typedef void (^JSBlock)(NSDictionary *dict);
+ (JSBlock)genBlock
{
NSString *ctn = @"JSPatch";
JSBlock block = ^(NSDictionary *dict) {
NSLog(@"I'm %@, version: %@", ctn, dict[@"v"])
};
return block;
}
@end// JS
var blk = require('JPObject').genBlock();
blk({v: "0.0.1"}); //output: I'm JSPatch, version: 0.0.1The self in defineClass() can't use in the async block, you should catch it if you want to use it in the block:
defineClass("JPViewController", {
viewDidLoad: function() {
var slf = self;
require("JPTestObject").callBlock(block(function(){
//`self` is not available here, use `slf` instead.
slf.doSomething();
});
}
}There is 2 limitation when passing block from JS to Obj-C:
A. Only supports up to 4 params. (you can modify the source code if you want more)
B. Params types can not be double.
##6. __weak / __strong
Use __weak() in JS to declare a weak variable, usually use to avoid retain circle.
For example, to avoid retain circle in block, we usually writing like this:
- (void)test {
__weak id weakSelf = self;
[self setCompleteBlock:^(){
[self blabla];
}]
}We can translate to JS like this:
var weakSelf = __weak(self)
self.setCompleteBlock(block(function(){
weakSelf.blabla();
}))If we want to strongify the weak variable before using it, use __strong():
var weakSelf = __weak(self)
self.setCompleteBlock(block(function(){
var storngSelf = __strong(weakSelf)
strongSelf.blabla();
}))##7. GCD
Use dispatch_after() dispatch_async_main() dispatch_sync_main() dispatch_async_global_queue() to call GCD.
// Obj-C
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
// do something
});
dispatch_async(dispatch_get_main_queue(), ^{
// do something
});// JS
dispatch_after(1.0, function(){
// do something
})
dispatch_async_main(function(){
// do something
})
dispatch_sync_main(function(){
// do something
})
dispatch_async_global_queue(function(){
// do something
})##8. Passing id* parameters
If you are calling a method which have id* parameters like NSError **, you can pass a
pointer to it, follow these steps:
- use
malloc(sizeof(id))to create a pointer. - pass pointer to the method.
- use
pval()to get the object. - use
releaseTmpObj()to release object after used. - use
free()to release pointer.
For example:
//OC
- (void)testPointer:(NSError **)error {
NSError *err = [[NSError alloc]initWithDomain:@"com.jspatch" code:42 userInfo:nil];
*error = err;
}//JS
//malloc() pval() free() is provided by JPMemory extension
require('JPEngine').addExtensions(['JPMemory'])
var pError = malloc(sizeof("id"))
self.testPointer(pError)
var error = pval(pError)
if (!error) {
console.log("success")
} else {
console.log(error)
}
releaseTmpObj(pError)
free(pError)