[英]method chaining returning undefined
I have the following javascript class 我有以下javascript类
var a = function () {
this.data = {};
};
a.prototype.parseString = function (string) {
this.data = string.split(',');
}
a.prototype.performOperationB = function () {
this.iPo = _.map(this.data, function () {
if (item.indexOf('ip') > -1) {
return item;
}
});
}
a.prototype.save = function (string) {
this.parseString(string)
.performOperationB()
// some other chained methods
}
var b = new a();
b.save(string);
would return TypeError: Cannot read property 'performOperationB' of undefined
将返回
TypeError: Cannot read property 'performOperationB' of undefined
Is it possible to chain the prototype methods one after another inside another method ? 是否可以在另一种方法内将原型方法一个接一个地链接?
Return this
from 返回
this
从
a.prototype.parseString = function(string) {
this.data = string.split(',');
return this;
}
because now method returns undefined
因为现在方法返回
undefined
var a = function () { this.data = {}; }; a.prototype.parseString = function (string) { this.data = string.split(','); return this; } a.prototype.performOperationB = function () { this.iPo = _.map(this.data, function (item) { if (item.indexOf('ip') > -1) { return item; } }); } a.prototype.save = function (string) { this.parseString(string) .performOperationB() } var b = new a(); b.save('string');
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