How does Object.keys work when applied to a Javascript variable? -

-

i have code in application this:

   var msg = data.data.modelstate[object.keys(data.data.modelstate)[0]];

can please explain object.keys part of code doing , give me idea data.datamodelstate object looks like.

right understanding code not working code around not can't debug find out.

object.keys() returns array of keys of object. in code, accessing first element of array. i.e. first key of data.data.modelstate.

this code value of first key of data.data.modelstate.

for example

suppose 

 data.data.modelstate={tmpkey:"some value"}  var msg = data.data.modelstate[object.keys(data.data.modelstate)[0]];  console.log(object.keys(data.data.modelstate)[0]); //will print ["tmpkey"]  console.log(msg); //it print "some value";

you can access key of object using []; , here accessing first key.

var msg = data.data.modelstate[object.keys(data.data.modelstate)[0]];

this become

var msg = data.data.modelstate[["tmpkey"][0]];

and become

var msg = data.data.modelstate["tmpkey"]; //simply return value of tmpkey property.

Comments

Post a Comment

Popular posts from this blog

python - pip install -U PySide error -

-
does know how avoid following error when running pip install -u pyside per official website instructions here: https://pypi.python.org/pypi/pyside/#installing-pyside-on-a-mac-os-x-system note have done brew install qt successfully. you using pip version 7.0.3, version 7.1.2 available. should consider upgrading via 'pip install --upgrade pip' command. collecting pyside using cached pyside-1.2.4.tar.gz installing collected packages: pyside running setup.py install pyside complete output command /applications/anaconda/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/dy/ttgqhqqx3g9bsbsnqnxsk2z80000gq/t/pip-build-cpxemt/pyside/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/dy/ttgqhqqx3g9bsbsnqnxsk2z80000gq/t/pip-0r7hri-record/install-record.txt --single-version-externally-managed --compile: ...
Read more

arrays - C++ error: a brace-enclosed initializer is not allowed here before ‘{’ token -

-
simple question: i'm trying initialize array within c++ class declaration: using namespace std; #include <string> class myclass{ public: string myarray[] = {"a","b","c"}; }; and i'm getting error: error: brace-enclosed initializer not allowed here before ‘{’ token no, without complied c++11 compiler, cannot initialize member array in declaration. have initialize array member in constructor. , don't use open array if know number of elements initialize array.
Read more

cytoscape.js - How to add nodes to Dagre layout with Cytoscape -

-
i trying add nodes dagre graph through cityscape.js. problem nodes not painted. code have: cy.add({ group: "nodes", data: { id:"n0",name:"n0",weight: 75 }, }); $.ajax(url).done(function(jsontree){ var newnodes=[]; for(var i=1;i<6;i++){ //var child = jsontree.result[i]; newnodes.push( { group: "nodes", data: { id: "n"+i, name:"n"+i}}, { group: "edges", data: { id: "e"+i, source: "n0", target: "n"+i } } ); } cy.add(newnodes); any ideas? have used loaded function reload graph not work. not know if have use specific function reload graph. thank in advance. you need add positions new nodes. cytoscape.js docs : it important note positions of newly added nodes must defined when calling cy.add(). nodes can not placed in graph without valid position — otherwise not displayed. yo...
Read more