cannot get field object with getByInternalNameOrTitle even though it shows up in enumeration using CSOM/JSOM

Question

I am using CSOM/JSON to get field data for a list. If I enumerate the list fields I get the field data/object. But if I look for one using getByInternalNameOrTitle I get the error "The property or field has not been initialized. It has not been requested or the request has not been executed. It may need to be explicitly requested.".

The code below prints all the fields in that first console.log but that second one results in an error. What gives?

ExecuteOrDelayUntilScriptLoaded(function()
{
    var clientContext = SP.ClientContext.get_current();
    var list = clientContext.get_web().get_lists().getByTitle("Meeting Agenda Items");
    this.listFields = list.get_fields();
    clientContext.load(this.listFields);


    clientContext.executeQueryAsync(Function.createDelegate(this, listFieldsLoaded), Function.createDelegate(this, function(){alert("error 1");}));
}, "sp.js");

function listFieldsLoaded()
{
    // if i enumerate the list fields this works fine
    var fieldEnumerator = listFields.getEnumerator();
    while(fieldEnumerator.moveNext())
    {
        var thisField = fieldEnumerator.get_current();
        console.log(thisField.get_internalName());
    }

    // but if i try to get it by an internal name
    // then it does not
    var thisField = listFields.getByInternalNameOrTitle("Title");
    console.log(thisField.get_internalName());
}

Answer 1

You need to load the thisField variable into the context.

var thisField;

ExecuteOrDelayUntilScriptLoaded(function()
{
    var clientContext = SP.ClientContext.get_current();
    var list = clientContext.get_web().get_lists().getByTitle("Meeting Agenda Items");
    this.listFields = list.get_fields();
    clientContext.load(this.listFields);
    thisField = listFields.getByInternalNameOrTitle("Title");

    clientContext.load(thisField);

    clientContext.executeQueryAsync(Function.createDelegate(this, listFieldsLoaded), Function.createDelegate(this, function(){alert("error 1");}));
}, "sp.js");

function listFieldsLoaded()
{
    // if i enumerate the list fields this works fine
    var fieldEnumerator = listFields.getEnumerator();
    while(fieldEnumerator.moveNext())
    {
        var thisField = fieldEnumerator.get_current();
        console.log(thisField.get_internalName());
    }


    console.log(thisField.get_internalName());
}

This will return the field name. (you can move the variable somewhere and pass it as a parameter) I was just doing this quickly.

Answer 2

why not set it before you add it to the context:

single field into the context:

ExecuteOrDelayUntilScriptLoaded(function()
{
    var clientContext = SP.ClientContext.get_current();
    var list = clientContext.get_web().get_lists().getByTitle("Meeting Agenda Items");
    this.listFields = list.get_fields().getByInternalNameOrTitle("Title");
    clientContext.load(this.listFields);


    clientContext.executeQueryAsync(Function.createDelegate(this, listFieldsLoaded), Function.createDelegate(this, function(){alert("error 1");}));
}, "sp.js");

function listFieldsLoaded()
{
    console.log(listFields.get_internalName());
}

or

all fields into the context:

ExecuteOrDelayUntilScriptLoaded(function()
{
    var clientContext = SP.ClientContext.get_current();
    var list = clientContext.get_web().get_lists().getByTitle("Meeting Agenda Items");
    this.listFields = list.get_fields();
    clientContext.load(this.listFields);


    clientContext.executeQueryAsync(Function.createDelegate(this, this.listFieldsLoaded), Function.createDelegate(this, function(){alert("error 1");}));
}, "sp.js");

function listFieldsLoaded()
{
    console.log(listFields.get_fields().getByInternalNameOrTitle("Title").get_internalName());
}