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The page "JavascriptPatternViewCommonJs" has been deleted by JoanTouzet:

https://wiki.apache.org/couchdb/JavascriptPatternViewCommonJs?action=diff&rev1=4&rev2=5

Comment:
Migrated to 
http://docs.couchdb.org/en/2.1.1/query-server/javascript.html#commonjs-modules

- <<Include(EditTheWiki)>>
  
- = Javascript Pattern to Share Code Between View and Other Functions =
- 
- This works only if one is using CouchApp since this pattern is dependent on 
CouchApp directives.
- 
- CouchApp directives are explained here: 
[[http://japhr.blogspot.com/2010/02/couchapp-templates-for-showing.html|Chris 
Strom's blog]].
- 
- == Shared Code ==
- 
- The following Javascript code fragment can be used as an example of a shared 
library between a View Map function and other functions (in this example, a 
validate_update_doc function). In the design document, create an entry under 
vendor.myComp.utils which is:
- 
- {{{#!highlight javascript
- var utils = {
- 
-    isArray: function(o) {
-       if( typeof(o) !== 'object' ) return false;
-       if( typeof(o.length) !== 'number' ) return false;
-       if( typeof(o.push) !== 'function' ) return false;
-       if( typeof(o.pop) !== 'function' ) return false;
-       if( typeof(o.concat) !== 'function' ) return false;
-       if( typeof(o.join) !== 'function' ) return false;
-       if( typeof(o.slice) !== 'function' ) return false;
-       if( typeof(o.reverse) !== 'function' ) return false;
-       if( typeof(o.splice) !== 'function' ) return false;
-       if( typeof(o.sort) !== 'function' ) return false;
- 
-       return true;
-    }
- };
- 
- // CommonJS bindings
- if( typeof(exports) === 'object' ) {
-    exports.isArray = utils.isArray;
- };
- }}}
- 
- Notes:
-   1. In a couchApp (an application developed and deployed using CouchApp), 
the content above would be saved in a file named "vendor/myComp/utils.js". 
-   1. Files uploaded using CouchApp are stripped of their extensions since it 
would lead to confusion as the dot (period) is the natural Javascript 
separator. Therefore, the shared code is "known" by CouchApp as 
"vendor/myComp/utils.js"  while it is referred internally to the design 
documents as "vendor.myComp.utils".
- 
- == Inclusion using CommonJs ==
- 
- Using CommonJs, the library defined above (shared code) would be included in 
a "validate_update_doc" function as follows:
- 
- {{{#!highlight javascript
- function(newDoc, oldDoc, userCtxt) {
-       
-    var myUtils = require('vendor/myComp/utils');
-    
-    // Verify geometries
-    if( newDoc.type === 'myDoc' ) {
- 
-       // Verify that list is an array
-       if( !myUtils.isArray(newDoc.list) ) {
-          throw( {forbidden: 'Invalid or missing list'} );
-       }
-    }
- }
- }}}
- 
- Notes:
-   1. The 'require' function in CommonJs exposes the 'exports' defined in the 
library and assigns them to the variable.
-   1. The variable 'myUtils' can be used to access the definitions from the 
shared code.
-   1. Note that the path uses slashes and that the file extension (if using 
CouchApp) is omitted. 
- 
- == Inclusion using CouchApp directives ==
- 
- Since View Map and View Reduce functions do not have access to CommonJs, the 
way one can include shared code within those functions is to use CouchApp 
directives. More specifically, in CouchApp, the 'code' directive instructs the 
tool to include the content of another file (verbatim) at the location of the 
directive before uploading the file to CouchDb.
- 
- An example of View Map function that shares the code defined above:
- 
- {{{#!highlight javascript
- function(doc) {
-       
-    // !code vendor/myComp/utils.js
-    
-    // Verify that list is an array
-    if( utils.isArray(doc.list) ) {
-       for(var i=0,e=doc.list.length; i<e; ++i) {
-          emit(doc.list[i],doc);
-       }
-    }
- }
- }}}
- 
- Since CouchApp includes the whole file at the point of the directive, the 
resulting content uploaded for this map function is:
- 
- 
- {{{#!highlight javascript
- function(doc) {
-       
-    var utils = {
-    
-       isArray: function(o) {
-          if( typeof(o) !== 'object' ) return false;
-          if( typeof(o.length) !== 'number' ) return false;
-          if( typeof(o.push) !== 'function' ) return false;
-          if( typeof(o.pop) !== 'function' ) return false;
-          if( typeof(o.concat) !== 'function' ) return false;
-          if( typeof(o.join) !== 'function' ) return false;
-          if( typeof(o.slice) !== 'function' ) return false;
-          if( typeof(o.reverse) !== 'function' ) return false;
-          if( typeof(o.splice) !== 'function' ) return false;
-          if( typeof(o.sort) !== 'function' ) return false;
- 
-          return true;
-       }
-    };
- 
-    // CommonJS bindings
-    if( typeof(exports) === 'object' ) {
-       exports.isArray = utils.isArray;
-    };
-    
-    // Verify that list is an array
-    if( utils.isArray(doc.list) ) {
-       for(var i=0,e=doc.list.length; i<e; ++i) {
-          emit(doc.list[i],doc);
-       }
-    }
- }
- }}}
- 
- Notes:
-   1. In this case, the CommonJs bindings are ignored since 'exports' is not 
defined in a View Map function.
-   1. The shared code is accessed via the variable named 'utils' defined in 
the external content file.
-   1. The CouchApp directive requires the file extension.
- 

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