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Update ko.datasource.js to synchronise multiple invokes and extend to add ajax capabilities #5

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Update ko.datasource.js to synchronise multiple invokes and extend to add ajax capabilities #5

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Update ko.datasource.js to synchronise multiple invokes and extend to…
agrath Oct 25, 2013
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Handle metadata for paging in response ajax object when using built i…
agrath Dec 11, 2013
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255 changes: 218 additions & 37 deletions ko.datasource.js
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Original file line number Diff line number Diff line change
@@ -1,79 +1,260 @@
/*! https://github.com/CraigCav/ko.datasource */
(function ( ko ) {
function datasource( source, target ) {
(function (ko) {
function datasource(source, target) {
var _target = target || ko.observable(),
paused = true,
trigger = ko.observable( false ),
loading = ko.observable( false ),
result = ko.computed( {
trigger = ko.observable(false),
loading = ko.observable(false),
result = ko.computed({
read: function () {
if ( paused ) {
if (paused) {
paused = false;
trigger( true );
trigger(true);
}
return _target();
},
write: function ( newValue ) {
_target( newValue );
loading( false );
write: function (newValue) {
_target(newValue);
loading(false);
},
deferEvaluation: true
} );
}),
async = false,
callback = function (state, value) {
var source = state.source, isAsync = state.isAsync, sync = state.sync
if (target.pager && value.meta) {
if (!isAsync) {
result(value.data);
result.pager.totalCount(value.meta.count);
} else {
if (source.sync == sync) {
result(value.data);
target.pager.totalCount(value.meta.count);
}
}
} else {
if (!isAsync) {
result(value);
} else {
if (source.sync == sync) {
result(value);
}
}
}
},
curry = function (fn) {
var slice = [].slice,
args = slice.call(arguments, 1);
return function () {
return fn.apply(this, args.concat(slice.call(arguments)));
};
},
isFunction = function(obj) {
return !!(obj && obj.constructor && obj.call && obj.apply);
},
//parseJSON borrowed from jQuery
parseJSON = function (data) {
if (!data) return null;
var rvalidchars = /^[\],:{}\s]*$/,
rvalidbraces = /(?:^|:|,)(?:\s*\[)+/g,
rvalidescape = /\\(?:["\\\/bfnrt]|u[\da-fA-F]{4})/g,
rvalidtokens = /"[^"\\\r\n]*"|true|false|null|-?(?:\d+\.|)\d+(?:[eE][+-]?\d+|)/g;
// Attempt to parse using the native JSON parser first
if ( window.JSON && window.JSON.parse ) {
return window.JSON.parse( data );
}
if ( typeof data === "string" ) {
// Make sure leading/trailing whitespace is removed (IE can't handle it)
data = jQuery.trim( data );
if ( data ) {
// Make sure the incoming data is actual JSON
// Logic borrowed from http://json.org/json2.js
if ( rvalidchars.test( data.replace( rvalidescape, "@" )
.replace( rvalidtokens, "]" )
.replace( rvalidbraces, "")) ) {

return ( new Function( "return " + data ) )();
}
}
}

jQuery.error( "Invalid JSON: " + data );
},
//tinyxhr by Shimon Doodkin - https://gist.github.com/4706967
tinyxhr = function (url, callback, method, contentType, timeout, params) {
var requestTimeout,xhr;
try{ xhr = new XMLHttpRequest(); }catch(e){
try{ xhr = new ActiveXObject("Msxml2.XMLHTTP"); }catch (e){
if(console)console.log("tinyxhr: XMLHttpRequest not supported");
return null;
}
}
var requestTimeout = setTimeout(function() {xhr.abort(); cb(new Error("tinyxhr: aborted by a timeout"), "",xhr); }, timeout || 10000);
xhr.onreadystatechange = function () {
if (xhr.readyState != 4) return;
clearTimeout(requestTimeout);
if (!xhr.aborted) {
callback(parseJSON(xhr.responseText), xhr.status != 200 ? new Error("tinyxhr: server response status is " + xhr.status) : false, xhr);
}
};
xhr.open(method?method.toUpperCase():"GET", url, true);
if (!params) {
xhr.send();
}
else {
xhr.setRequestHeader('Content-type', contentType ? contentType : 'application/x-www-form-urlencoded');
var serialize = function (obj) {
var str = [];
for (var p in obj) {
if (obj.hasOwnProperty(p)) {
str.push(encodeURIComponent(p) + "=" + encodeURIComponent(obj[p]));
}
}
return str.join("&");
}
if (typeof (params) == 'object') {
params = serialize(params);
}
xhr.send(params)
}
return xhr;
},
query = function(settings, async, callback){
if (!query.params) {
query.params = ko.computed(function () {
if (settings.params) {
if (target.pager) {
var limit = target.pager.limit();
var page = target.pager.page();
settings.params.skip = (page-1) * limit;
settings.params.take = limit;
}
var serialized = JSON.stringify(settings.params, function (key, value) {
if (!ko.isObservable(value)) return value;
return ko.utils.unwrapObservable(value);
});

return JSON.parse(serialized);
}
return null;
})
};

ko.computed( function () {
if ( !trigger() ) return;
loading( true );
source.call( result );
} );
if (query.xhr && async) {
query.xhr.aborted = true;
query.xhr.abort();
query.xhr = null;
}
query.xhr = tinyxhr(settings.url, callback, settings.method || 'POST', settings.contentType, settings.timeout, query.params());
};
if (source.generator) {
async = source.async;
if (isFunction(source.generator)) {
source = source.generator;
} else {
source = curry(query, source.generator, async);
}
}
var generator = function () {
source.sync = (source.sync || 0) + 1 ;
var callbackInstance = curry(callback, { sync: source.sync, isAsync: async, source: source });
source.call(result, callbackInstance);
};
ko.computed(function () {
if (!trigger()) return;
loading(true);
generator.call(result);
});

result.refresh = function () {
trigger( trigger() + 1 );
trigger(trigger() + 1);
};

result.loading = loading;

return result;
}

function Pager( limit ) {
this.page = ko.observable( 1 );
this.totalCount = ko.observable( 0 );
this.limit = ko.observable( limit );
function Pager(limit) {
this.page = ko.observable(1);
this.totalCount = ko.observable(0);
this.limit = ko.observable(limit);

this.totalPages = ko.computed( function () {
var count = Math.ceil( ko.utils.unwrapObservable( this.totalCount ) / ko.utils.unwrapObservable( this.limit ) )
this.totalPages = ko.computed(function () {
var count = Math.ceil(ko.utils.unwrapObservable(this.totalCount) / ko.utils.unwrapObservable(this.limit))
return count == 0 ? 1 : count;
}, this );
}, this);

this.pages = ko.computed(function () {
var a = [];
var count = this.totalPages();
for (var p = 0; p < count; p++) {
a.push(p + 1);
}
return a;
}, this);

this.next = function () {
var currentPage = this.page();
this.page( currentPage + 1 );
} .bind( this );
var next = currentPage + 1;
if (next > this.totalPages()) {
next = this.totalPages();
}
this.page(next);
}.bind(this);

this.previous = function () {
var currentPage = this.page();
this.page( currentPage === 0 ? 0 : currentPage - 1 );
} .bind( this );
var prev = currentPage === 0 ? 0 : currentPage - 1;
if (prev > this.totalPages()) {
prev = this.totalPages();
}
if (prev > 0) {
this.page(prev);
}
}.bind(this);

this.specific = function (page) {
if (page > 0 && page < this.totalPages()) {
this.page(page);
}
}.bind(this);

this.first = function () {
this.page( 1 );
} .bind( this );
this.page(1);
}.bind(this);

this.last = function () {
this.page( this.totalPages() );
} .bind( this );
this.page(this.totalPages());
}.bind(this);

this.isFirstPage = ko.computed(function () {
return this.page() == 1;
}, this);

this.isLastPage = ko.computed(function () {
return this.page() == this.totalPages();
}, this);

this.isNextPageAvailable = ko.computed(function () {
return !(this.isLastPage());
}, this);

this.isPrevPageAvailable = ko.computed(function () {
return !(this.isFirstPage());
}, this);
}

ko.extenders.datasource = function ( target, source ) {
var result = datasource( source, target );
ko.extenders.datasource = function (target, source) {
var result = datasource(source, target);
result.options = target.options || {};
return result;
};

ko.extenders.pager = function ( target, options ) {
var pager = new Pager( options.limit || 10 );
ko.extenders.pager = function (target, options) {
var pager = new Pager(options.limit || 10);
target.options = target.options || {};
target.options.pager = target.pager = pager;
return target;
};
} )( ko );
})(ko);