context, flowContext, globalContext help me understand pls
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Toshi Bass
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Aug 12, 2017, 12:31:25 PM8/12/17
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I have always used context.global.whatever successfuly
recently I've been using context.get and context.set fine
example:
var count = context.get('count') || 0;
count += 1;
context.set('count',count);
msg.payload=count;
return msg;
so thought I would try flow context and global context but reading the documentation for flow context see below just doesn't work for me.
if I include var flowContext = this.context().flow; results in "TypeError: this.context is not a function"
var count = flowContext.get('count')||0; results in "ReferenceError: flowContext is not defined (line 4, col 38)" as does var count = globalContext.get('count')||0;
What does work is var count = flow.get('count')||0; and var count = global.get('count')||0; so is this a typo on https://nodered.org/docs/creating-nodes/context or am I missing something ?
example:
var count = flow.get('count') || 0;
count += 1;
flow.set('count',count);
msg.payload=count;
return msg;
or
var count = global.get('count') || 0;
count += 1;
global.set('count',count);
msg.payload=count;
return msg;
Flow context
The flow-level context is shared by all nodes on a given tab.
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You are reading the docs about creating nodes in the runtime. I assume you're writing this code in a Function node - so you should see what the 'writing functions' docs say about accessing context.
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Your statement:
var ssd = flow.get('ssd')||"Off";
Is dealing with two variables a local 'ssd' variable and a flow variable 'ssd'. Think of the ssd in 'var ssd' as being called 'x'. So you could write it as:
var x = flow.get('ssd')||"Off";
So are you trying to initialize 'x' or the flow variable 'ssd'
If you want to initialize the flow variable 'ssd' then you have to do it somewhere. You could try
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Yes I agree "two variables"
I was thinking the same thing but it doesn't work .. flow.set('ssd') = flow.get('ssd')||"Off"; red X Bad Assignment Expected assignment or function call bla bla
In fact my function doesn't work ether or should I say its working now but if I try to copy the function and change flow.get('ssd') to flow.get('ssd1') the new function doesn't initiate ssd1 so I conclude .. whilst I was writing this function I initiated ssd as Off and that's persisted whilst I changed my code.
Toshi Bass
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Sep 19, 2017, 6:39:43 AM9/19/17
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YES that's solved, thanks Nick
context.set('ssd', context.get('ssd')||'Off'); replaces the old context.global.ssd = context.global.ssd || 0; and works for context, flow and global gets.
