--- title: Add flags to Stock chart when Form4 trades were filed slug: add-flags-to-stock-chart-when-form4-trades-were-filed published_at: 2021-04-21 17:00:33 +0000 updated_at: 2026-03-04 20:14:17 +0000 summary: description: In this episode, we'll build an API endpoint to return some simple form4 data to display on our stock charts with Ruby on Rails. #rails #rubyonrails tags: [] views: 218 author: CJ Avilla url: https://www.cjav.dev/videos/add-flags-to-stock-chart-when-form4-trades-were-filed youtube_url: https://www.youtube.com/watch?v=uhH0WBkP2Yc youtube_id: uhH0WBkP2Yc embed_url: https://www.youtube.com/embed/uhH0WBkP2Yc thumbnail_url: https://i.ytimg.com/vi/uhH0WBkP2Yc/hqdefault.jpg type: video --- # Add flags to Stock chart when Form4 trades were filed *Published: April 21, 2021* *Views: 218* ## Watch [Watch on YouTube](https://www.youtube.com/watch?v=uhH0WBkP2Yc) [![Add flags to Stock chart when Form4 trades were filed](https://i.ytimg.com/vi/uhH0WBkP2Yc/hqdefault.jpg)](https://www.youtube.com/watch?v=uhH0WBkP2Yc) ## Description In this episode, we'll build an API endpoint to return some simple form4 data to display on our stock charts with Ruby on Rails. #rails #rubyonrails ## Transcript what's up everyone welcome back in the previous episode we went through the tedious process of ingesting some form 4 data from the sec we've got it in the database at least for a few recent filings and in this episode we're going to show how to add flags to our javascript chart that shows up uh on the browser for each individual company when a trade happen it will show a little bit of information about the insider who traded it and then maybe like how big the trade was so what i want to do now is um let's let's just fire up rail server and take a look at our uh our high chart uh stock charts that we have like sort of populating on the page so we'll go to localhost 3000 and pull up uh-huh we've got uh companies i think slash companies might drop us into a list of companies here okay cool so here is where we have a list of a bunch of companies and if you look at a specific company like microsoft um we should see the um the data for the company let's go back to all companies i think we might have price data i might have wiped out the price data so let's fetch the price data for a given company here so let's see rails c i think we like blew away the database and then re migrated it uh all right so we have a job for fetching price data so if we go to app jobs fetch company prices job and if we perform this on the pager duty perform now for the first company we should full and pull in some prices from from an api from a stock price api and then here i'm seeing some 404s ah right because we need to run um we need to run our webpacker thing also let's split this vertically and then say dev slash or is it bin slash web pack dev server here we go uh oh gosh so npm install orgash node n version node end local this one i can't remember which version of node we need to use in order to get webpack are behaving uh okay so let's see if this is going to give us there we go all right so now webpackers is back up and running this is our high high chart stock chart that um that is showing on the page uh and if you recall so if we go back let's see does does microsoft wait company let's try two okay so microsoft has prices too and if we stretch it out you'll see the flags that already exist here so there was some there was some dummy data that came from high charts to add these flags so let's go take a look at that now so if you go to high charts js at the very at the very bottom here we see the series which gives us a couple different series so at the top we have the price series this is like the price data and then the bottom is the flags which is um all of the the like things that are showing up here as this abc so we want to add something similar to these flags for the trades that are happening on microsoft or the trades that are happening for that given company so we have the trades in um in the database saved as form four so we say form form four dot last dot company or actually here we see the company id here four three two nine so if we copy that and drop it into our url this should pull up carvana um we have not fetched prices for carbana so let's do that so we are going to say fetch prices for carvana and now if we refresh the page okay so now we see the price data for carvana cvna now for this trade right form four dot last so form four number 29 the file date was wednesday the 14th of april 2021 so on wednesday the 14th of april over here on the very far right we want a flag to appear for this trade that says you know how many how many shares were sold basically and so what we need to do is look at the shape of the data that's returned here or the shape of the data that's expected and it looks like we need a date a title and then some text i think the title is just like kind of what we see in the circle and then the text is what we see when we hover over it and then we see the date here so what i want to do is create a new api endpoint for filings and we'll call it we'll actually call it flags it'll be very similar to prices so up here we have an api endpoint for fetching the prices for a given company we'll do the same thing for for for trades so let's actually call or maybe form for let's call it flags because we'll just return like very limited data that's just so specific to um rendering these uh to rendering these flags okay so let's say rails g controller api flags and yeah this will create a new controller in the api namespace api flags controller and we can say module api and then we'll take this off and okay here we go so let's add a index action that will expect a company id to be passed and we're going to say like company is equal to company. find params company id and we want to look up the form four so i think we have a relation or an association on the company to each form four yeah so it has many form fours so we can say uh company.form fours let's actually just render the json for all the form force and see how wild that looks uh so if we come over here and we go to like um api flags slash or like gosh what was the what was the id i forget uh uh four four three two nine so that's going to be the company id so we say question mark company id is equal to that and we want to say api flags and this should give us back some json data once we add a route so resources flags all right cool so this is some json data that we got back has the id the link a whole bunch of information about what happened here including the insider's id whether they're director officer etc etc so what let's see what is the actual data that we want out of the trade i think it might just be the sum of the shares and potentially uh so yeah question there's a question an open question about like how much of this should be um let's see how much of it should be shown on the flag versus how much of it do we want to show when we're generally just fetching this so yeah i kind of think we want to like we definitely want to know uh the number of shares so i think that that might be worth keeping as part of the text right so if we go back to this company's 43.29 so the text some event with description like i think instead of abc i think we want to see like was it a buy or a cell which we could do by saying is the sum of the shares positive or negative um so so a couple questions in my mind like one should we just be like passing the entire filing back or should we be part like figuring out what to render back from the controller action so yeah like i think we want to render back like f let's see so x is going to be the date so filing or f dot file date i think it's called let's see uh form four uh yeah f.file date is going to be x and then what were the other things that it had let's see hi charts um title and text so we need to figure out what the title is going to be and what the text is going to be so for the title let's just let's just put x for now and then the text will put f dot sum shares um and let's refresh hmm i'm surprised it's not okay render json for actually yeah let's just say like flags are these things render json for flags okay there we go so now we have the x we have the title and we have the text now the x i think needs to be actually parsed into a date object so here we can say like um this is grabbing the price data we also want to grab the the flag data and the way that we're going to grab the flag data is by hitting api flags and passing in the company id and then when we get back some flag data we're going to say iterate over the flag data and that is going to give us x title and text so we want to map over x title and text and we want to return x title and text but we want to parse the uh the x date all right so now and then yeah i guess at the bottom then we want to use that instead of data here we want to use flags right all right let's just take it for a spin and see see how that goes uh okay let's open up the terminal go to the sources tab refresh the page uh we should be hitting the back end let's see webpack packs high charts let's just double check to make sure that the data is actually what we expect it is on this at this point so flags should be um oh gosh undefined okay so what um oh you know what this it's a curly brace the curly brace situation because um yeah so if we put curly braces after the arrow function it expects us expects that we're returning something um all right so we gotta i think we have to wrap it like that maybe failed to compile why is it failing to compile now um yeah let's break this onto multiple lines is that going to compile failed to compile why is it failing to compile data parse is that not a is that not a thing oh yeah x points it yeah that doesn't make any sense okay so here we go all right what um so what does this look like now flags hey we've got some data okay can you see that let's see i can barely see that let's see so we have nan undefined undefined okay so what about flag data flag data uh has some stuff if we come into here and we see x x is undefined why why is it undefined um object dot entries for flag data what does that give us an array with two objects um oh wait do we i don't think we even need wait yeah i'm trying to remember why we're doing dot entries uh i don't know if we even need entries i think we need because flag data is already an array yeah so we should be able to just say flag data dot map right okay now is x something x is that so date dot parse x is that and title and text and we should be good to go all right so text might need to be like a string or something interesting like that let's see hey look at that we've got an x so cool all right so if we hover over it we see how many shares are traded that is awesome all right so now we are rendering flags onto onto the chart here so that's super cool uh what i think we want to do is change the the text to be um or maybe we can change the color of the flag so now we want to like start digging into the actual like the real uh api for high charts to figure out how we can really make this um interesting so the shape maybe we want to change the shape from being a circle pin to some other kind of pin or i don't know like maybe the flag the flag like um it could be like a different color or something or have some other things so let's see if we can figure out from the docks here um some sort of other [Music] uh some other ways that we can style our flags so high chart stock charts that's what we're passing in and the series so the series data what can that be made out of so a series can have type flags and when it's a tight flag see how many there are here colors and clip and cursor and custom and data labels and grouping and all this stuff so we want to see if the type option is not specified it's going to be this type okay and then okay blah blah blah so uh flag shared option for all flags and then we have a series with type flags okay so what is color can we set the color when using dual or multiple axes let's just try changing the color while we're up here mapping over it so let's say like color is uh red i don't know i i'm like not sure what this api looks like but oh wow look at that okay so yeah that totally changed the color to red so i think what we might want to do is say like if the sum of the shares is less than zero then make it red otherwise we'll make it green or something so this will be this will be kind of like a handy spot to do some of that client-side modification for our flags the other thing too that i'm thinking is we could technically do this on the server yeah let's see so is so text is technically the sum of the shares so yeah i'm gonna i'm changing my mind let's go back to let's go back to uh our api endpoint so api flags controller and let's just return the um the sum shares and let's return let's see form four let's return the um let's return a little bit more so like is director dot is director let's return the name to insider name is f dot insider.name oh this is fun we're going to run into an n plus one query right here because we're not eager loading so we'll address that and then yeah so is director is officer diesel okay i think that should be good for the data that we'll want on the front end so let's go back to let's actually call this file date i'll go back to high charts stock chart thing here and then instead of this we'll say um so yeah we'll just say this is the filing or like f say f dot file date um and then the title is going to be like some concatenation of things but for now let's just do like f dot insider name and the or um let's keep this x for now and then we'll make the text f dot insider name and then f dot some shares i don't know we'll mess around with it a bit more uh okay so we've got a red x and then it tells us okay it tells us the name of the person who traded and what they traded this is cool this is really cool uh all right so um yeah let's do the title fda insider or officer title okay oh okay because in this case the insider is actually like an investment firm so that's that's fine let's actually take a look at another let's take a look at another form four uh forum ford uh first um that's in bitcoin or i'm sorry in coinbase um those are gonna be yeah so form four dot uh oh let's just take a look at a bunch of them coinbase coinbase coinbase coinbase coinbase coinbase coinbase coinbase all right let's see let's just pull up coinbase so this this is like a brand new company so we're not going to have like any price like there's not going to be very many prices or anything so i don't know how interesting it's going to be yeah so a bunch of trades happen like immediately right like people oh this is interesting though like folks are buying so that's actually like a really strong symbol if um if you've got insiders who are purchasing at ipo and obviously the price popped and is up a bit from the ipo price so that's cool that's actually like a really really strong positive signal for um for insiders is if there's insiders who work at the company who are buying at ipo that's that represents like a really really strong positive outlook for the company going forward um okay so let's say yeah i mean i want to try to find a form ford uh where the company id is not um is not this coinbase company because i want to look at some other some other form fours too all right so gii is some other company that i've never heard of um but if we go to that company now all right so now we see the x here it tells us the person who traded and they sold all right so this is this is actually looking pretty cool now in order for this to like be even more exciting and more fun what i think we want to do is just we need to like fetch way more form fours and plop them on the map but um for our purposes we've sort of done what we wanted to do well actually let's make the color yeah so we'll make the title like buy if it's a buy or sell if it's a cell so if f dot sum shares is greater than zero then it's a buy okay so then if it's a buy we want to say the um so if it's a buy one to be green and we're going to say this is a buy and otherwise it's going to be a cell and the text is the text and stuff is going to be the same whatever we can draw it up later but yeah here we go we see us this is a cell and we can see these are actually all are they all cells uh i think that's that's wrong yeah so if sean okay so is this um is this coming back as a string or something let's see so no some shares if some shares is greater than zero then it's a buy and uh so coinbase i thought we had some buys some shares maybe they were all sales okay so that's that's like less yeah that's less cool um oh yeah carvana was that one uh that was also a sale all right so let's find let's try to find a form four where uh some shares is greater than zero all right sling slng all right we got to like fetch the prices again all right there we go nice we see a buy okay cool all right so this is this is working as expected this was the goal for the the the episode um so in the next episode what i think we'll do is uh we'll go through and fetch like a bunch more filings um so that you don't have to watch going through that but we'll fetch a bunch more filings so that we can plot several more onto the map and then or onto the chart and then we'll experiment with some other stuff in the next one i don't know we'll figure out what we want to do the the goal again is we want to get to a point where we can sort of be polling on a periodic basis and then when a new trade happens that's sort of interesting because the insider previously purchased at a low and then sold at a high or something like that so that we can copy that insider and try to try to do the same thing they're doing especially for those micro cap companies so uh if you want to come back in the next one we will um yeah we'll do we'll do some more some more exercises to get us towards that end goal alright thanks so much for watching and we'll see in the next one --- [Back to all videos](https://www.cjav.dev/videos) --- ## Hey Agent, thanks for visiting! 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