JavaScript design mode 3

Portal Big Open Object

var book=function(isbn,title,author) {    ifthrownew Error ("illegal");     this. isbn=ISBN;     this. title=title| | ' No title ';     this. author| | ' No author ';} Book.prototype.display=function() {    ...};

Hardened version

varbook=function(isbn,title,author) {if(! This. CHECKISBN (ISBN))Throw NewError ("ISBN not valid");  This. isbn=ISBN;  This. title=title| | ' No title ';  This. author| | ' No author ';} Book.prototype={checkisbn:function(ISBN) {if(isbn==undefined| |typeofIsbn!= ' String ') {            return false; } ISBN=isbn.replace (/-/, "); if(isbn.length!=10 &&isbn.length!=13) {            return false; }        varSum=0; if(isbn.length===10) {            if(!isbn.match (/^\d{9}/)){                return false; }             for(vari=0;i<9;i++) {sum+=isbn.charat (i) * (10-i); }            varChecksum=sum%11; if(checksum===10) checksum= ' X '; if(Isbn.charat (9)! =checksum) {                return false; }        }        Else{            if(!isbn.match (/^\d{12}/)){                return false; }             for(vari=0;i<12;i++) {sum+=isbn.charat (i) * ((i%2===0)? 1:3); }            varChecksum=sum%10; if(Isbn.charat (12)! =checksum) {                return false; }        }        return true; }, display:function(){        ...    }};

Further

varpublication=NewInterface (' Publication ', [' getisbn ', ' setisbn ', ' getTitle ', ' settitle ', ' getauthor ', ' setauthor ', ' Display ']);varbook=function(isbn,title,author) { This. SETISBN (ISBN);  This. Settitle (title);  This. Setauthor (author);} Book.prototype={checkisbn:function(ISBN) {...}, GETISBN:function(){        return  This. ISBN; }, SETISBN:function(ISBN) {if(! This. CHECKISBN (ISBN))Throw NewError ("ISBN not valid");  This. isbn=ISBN; }, GetTitle:function(){        return  This. title; }, Settitle:function(title) { This. title=title| | " No title "; }, Getauthor:function(){        return  This. Author; }, Setauthor:function(author) { This. author=author| | " No author "; }, display:function(){        ...    }};

To prevent unintended use by other programmers, you can add _ to private methods and properties to indicate that they are private

Implementing private members with closures

varbook=function(newisbn,newtitle,newauthor) {varIsbn,title,author; functionCHECKISBN (ISBN) {...}  This. getisbn=function(){        returnISBN;    };  This. setisbn=function(NEWISBN) {if(!CHECKISBN (NEWISBN))Throw NewError ("ISBN not valid"); ISBN=NEWISBN;    };  This. gettitle=function(){        returntitle;    };  This. settitle=function(newtitle) {title=newtitle| | ' No title ';    };  This. getauthor=function(){        returnauthor;    };  This. setauthor=function(newauthor) {author=newauthor| | ' No author ';    };  This. SETISBN (NEWISBN);  This. Settitle (Newtitle);  This. Setauthor (Newauthor);}; Book.prototype={display:function(){        ...    }};

JavaScript design mode 3