Add Prettier

I haven't examined every single change. It's mostly single-quotes,
trailing commas, and indentation/linebreaking. A few places in
calculator.ts where parentheses were added:

```typescript
const c = something as string || '';
// becomes
const c = (something as string) || '';
```

This doesn't seem quite right to me -- I think it should just be
`something ?? ''`, or `(something ?? '') as OtherType` -- but I wanted
to keep this PR mechanical.

It turns out Prettier is also smart enough to prettify HTML and CSS
within template literals, which is very cool.

.prettierignore

@@ -0,0 +1,2 @@
+# Build products
+build

.prettierrc

@@ -0,0 +1,6 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all",
+  "arrowParens": "avoid",
+  "printWidth": 80
+}

README.md

@@ -3,19 +3,19 @@
 Takes functionality from our [public website calculator](https://www.rewiringamerica.org/app/ira-calculator) and packages it up in a custom web component built using `lit`. Lit's `Task` library takes care of watching the form parameters for changes
 and fetching data from our API.
 
-__Note:__ API keys are required, sign up on our [API homepage](https://www.rewiringamerica.org/api).
+**Note:** API keys are required, sign up on our [API homepage](https://www.rewiringamerica.org/api).
 
 # Documentation
 
- * [Embed usage](https://api.rewiringamerica.org/docs/v0/embed)
- * [Calculator examples](https://glitch.com/~rewiring-america-calculator-widget)
+- [Embed usage](https://api.rewiringamerica.org/docs/v0/embed)
+- [Calculator examples](https://glitch.com/~rewiring-america-calculator-widget)
 
 # Development
 
- * `yarn` to install dependencies
- * `yarn serve:widget` and open `http://localhost:1234/` to start working - should refresh when files change
- * Open `http://localhost:1234/working-copy.html` to test against the dev API service
- * `yarn build:widget` to build the deployment artifacts (Vercel does this for production deploys)
+- `yarn` to install dependencies
+- `yarn serve:widget` and open `http://localhost:1234/` to start working - should refresh when files change
+- Open `http://localhost:1234/working-copy.html` to test against the dev API service
+- `yarn build:widget` to build the deployment artifacts (Vercel does this for production deploys)
 
 # Styles
 
@@ -30,47 +30,52 @@ This site is deployed using the [embed-rewiring-america](https://vercel.com/rewi
 # TODO
 
 Features and content:
- * [x] Add remaining guidance and disclaimer copy for <80% and >150% AMI.
- * [ ] Add reset button to form?
- * [ ] Switch order of incentives depending on whether credits/rebates are more useful.
- * [x] Add currency formatting to the income input element. Using [autonumeric](http://autonumeric.org), which is large.
- * [ ] Consider [Inputmask](https://robinherbots.github.io/Inputmask/#/documentation/numeric) in future.
- * [x] Use a better tooltip component to ensure tooltips are readable at mobile breakpoints. Trying Shoelace's [tooltip](https://shoelace.style/components/tooltip).
- * [ ] Think about how the 'back to calculator' links should work on RA's detail pages ([example](https://www.rewiringamerica.org/app/ira-calculator/information/electrical-panel))
- * [ ] Add analytics support (Amplitude events?)
- * [ ] Add support for Spanish translations.
- * [ ] Send javascript events for calculate, results, project details clicks.
+
+- [x] Add remaining guidance and disclaimer copy for <80% and >150% AMI.
+- [ ] Add reset button to form?
+- [ ] Switch order of incentives depending on whether credits/rebates are more useful.
+- [x] Add currency formatting to the income input element. Using [autonumeric](http://autonumeric.org), which is large.
+- [ ] Consider [Inputmask](https://robinherbots.github.io/Inputmask/#/documentation/numeric) in future.
+- [x] Use a better tooltip component to ensure tooltips are readable at mobile breakpoints. Trying Shoelace's [tooltip](https://shoelace.style/components/tooltip).
+- [ ] Think about how the 'back to calculator' links should work on RA's detail pages ([example](https://www.rewiringamerica.org/app/ira-calculator/information/electrical-panel))
+- [ ] Add analytics support (Amplitude events?)
+- [ ] Add support for Spanish translations.
+- [ ] Send javascript events for calculate, results, project details clicks.
 
 Robustness:
- * [x] Take a copy of fonts and serve them from this domain.
- * [ ] Port to API v1's calculator endpoint.
- * [ ] Add slots to allow customizing the form intro text.
- * [x] Add UI tests with Cypress, run in CI.
- * [ ] Add unit tests, run in CI.
- * [ ] How do we handle versioning?
- * [ ] Work with Zuplo to add `origin` configs to API keys and prevent use of API keys outside specific hosts.
- * [ ] Generate types (and API client?) automatically from OpenAPI file.
- * [x] Protect main branch, require PRs.
+
+- [x] Take a copy of fonts and serve them from this domain.
+- [ ] Port to API v1's calculator endpoint.
+- [ ] Add slots to allow customizing the form intro text.
+- [x] Add UI tests with Cypress, run in CI.
+- [ ] Add unit tests, run in CI.
+- [ ] How do we handle versioning?
+- [ ] Work with Zuplo to add `origin` configs to API keys and prevent use of API keys outside specific hosts.
+- [ ] Generate types (and API client?) automatically from OpenAPI file.
+- [x] Protect main branch, require PRs.
 
 Optimizations:
- * [ ] Add support for caching results in localStorage.
- * [ ] Add support for showing default list of incentives (from `/api/v0/incentives`).
- * [ ] Reuse microcopy from Rewiring America's CMS to avoid duplication between this repo and our website.
+
+- [ ] Add support for caching results in localStorage.
+- [ ] Add support for showing default list of incentives (from `/api/v0/incentives`).
+- [ ] Reuse microcopy from Rewiring America's CMS to avoid duplication between this repo and our website.
 
 Roadmap:
- * [ ] Open source?
- * [ ] Do we need a way to filter the kinds of incentives offered?
- * [ ] Query by address for v1?
- * [ ] Respond to customer requests for customization/functionality.
+
+- [ ] Open source?
+- [ ] Do we need a way to filter the kinds of incentives offered?
+- [ ] Query by address for v1?
+- [ ] Respond to customer requests for customization/functionality.
 
 Bugs:
- * [ ] Clicking the tooltip for Household Income should focus the input. Do we need `delegatesFocus` or do we need to refactor the input into a slot so it's light DOM?
- * [ ] Tapping the tooltip on mobile probably shouldn't select the field. Move outside the label maybe?
+
+- [ ] Clicking the tooltip for Household Income should focus the input. Do we need `delegatesFocus` or do we need to refactor the input into a slot so it's light DOM?
+- [ ] Tapping the tooltip on mobile probably shouldn't select the field. Move outside the label maybe?
 
 # References
 
- * [Lit](https://lit.dev)
- * [Lit Task](https://github.com/lit/lit/tree/main/packages/labs/task)
- * [Rewiring America API](https://api.rewiringamerica.org/docs/)
- * [BEM](https://getbem.com/introduction/)
- * [Shoelace](https://shoelace.style)
+- [Lit](https://lit.dev)
+- [Lit Task](https://github.com/lit/lit/tree/main/packages/labs/task)
+- [Rewiring America API](https://api.rewiringamerica.org/docs/)
+- [BEM](https://getbem.com/introduction/)
+- [Shoelace](https://shoelace.style)

cypress.config.ts

@@ -1,7 +1,7 @@
-import { defineConfig } from "cypress";
+import { defineConfig } from 'cypress';
 
 export default defineConfig({
-  projectId: "4uypg2",
+  projectId: '4uypg2',
   e2e: {
     setupNodeEvents(on, config) {
       // implement node event listeners here

cypress/e2e/calculator.cy.ts

@@ -4,7 +4,8 @@ describe('template spec', () => {
     cy.get('rewiring-america-calculator').should('exist');
     // FIXME: is there a way to do this less repetitively?
     // Doing const shadow = cy.get(...).shadow() didn't seem to work.
-    cy.get('rewiring-america-calculator').shadow()
+    cy.get('rewiring-america-calculator')
+      .shadow()
       .contains('Upfront Discounts')
       .siblings()
       .contains('$14,000');
@@ -21,5 +22,5 @@ describe('template spec', () => {
     cy.get('rewiring-america-calculator')
       .shadow()
       .contains('Covers up to 50% of costs');
-  })
-})
+  });
+});

cypress/support/commands.ts

@@ -34,4 +34,4 @@
 //       visit(originalFn: CommandOriginalFn, url: string, options: Partial<VisitOptions>): Chainable<Element>
 //     }
 //   }
-// }
+// }

cypress/support/e2e.ts

@@ -14,7 +14,7 @@
 // ***********************************************************
 
 // Import commands.js using ES2015 syntax:
-import './commands'
+import './commands';
 
 // Alternatively you can use CommonJS syntax:
-// require('./commands')
+// require('./commands')

package.json

@@ -13,7 +13,8 @@
     "build:widget": "parcel build --target default",
     "serve:widget": "parcel serve ./src/*.html --dist-dir build",
     "cypress:open": "cypress open",
-    "cypress:run": "cypress run"
+    "cypress:run": "cypress run",
+    "lint": "prettier --check ."
   },
   "browserslist": {
     "production": [
@@ -33,6 +34,7 @@
     "parcel": "v2.8.3",
     "postcss": "^8.4.21",
     "postcss-modules": "^6.0.0",
+    "prettier": "^2.8.8",
     "typescript": "^4.9.5"
   },
   "main": "dist/calculator.js",