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Updating string templates to have test cases for all the main helpers we want to make use of and adding a readme.

This commit is contained in:
mike12345567 2021-01-25 17:08:21 +00:00
parent 1d38dda79b
commit a254567bec
7 changed files with 362 additions and 18 deletions

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@ -1,6 +1,6 @@
<script>
import groupBy from "lodash/fp/groupBy"
import { Button, TextArea, Drawer, Heading, Spacer } from "@budibase/bbui"
import { TextArea, Heading, Spacer } from "@budibase/bbui"
import { createEventDispatcher } from "svelte"
import { isValid } from "@budibase/string-templates"
import {

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@ -0,0 +1,73 @@
# String templating
This package provides a common system for string templating across the Budibase Builder, client and server.
The templating is provided through the use of [Handlebars](https://handlebarsjs.com/) an extension of Mustache
which is capable of carrying out logic. We have also extended the base Handlebars functionality through the use
of a set of helpers provided through the [handlebars-helpers](https://github.com/helpers/handlebars-helpers) package.
We have not implemented all the helpers provided by the helpers package as some of them provide functionality
we felt would not be beneficial. The following collections of helpers have been implemented:
1. [Math](https://github.com/helpers/handlebars-helpers/tree/master#math) - a set of useful helpers for
carrying out logic pertaining to numbers e.g. `avg`, `add`, `abs` and so on.
2. [Array](https://github.com/helpers/handlebars-helpers/tree/master#array) - some very specific helpers
for use with arrays, useful for example in automations. Helpers like `first`, `last`, `after` and `join`
can be useful for getting particular portions of arrays or turning them into strings.
3. [Number](https://github.com/helpers/handlebars-helpers/tree/master#number) - unlike the math helpers these
are useful for converting numbers into useful formats for display, e.g. `bytes`, `addCommas` and `toPrecision`.
4. [URL](https://github.com/helpers/handlebars-helpers/tree/master#url) - very specific helpers for dealing with URLs,
such as `encodeURI`, `escape`, `stripQueryString` and `stripProtocol`. These are primarily useful
for building up particular URLs to hit as say part of an automation.
5. [String](https://github.com/helpers/handlebars-helpers/tree/master#string) - these helpers are useful for building
strings and preparing them for display, e.g. `append`, `camelcase`, `capitalize` and `ellipsis`.
6. [Comparison](https://github.com/helpers/handlebars-helpers/tree/master#comparison) - these helpers are mainly for
building strings when particular conditions are met, for example `and`, `or`, `gt`, `lt`, `not` and so on. This is a very
extensive set of helpers but is mostly as would be expected from a set of logical operators.
## Format
There are two main ways that the templating system can be used, the first is very similar to that which
would be produced by Mustache - a single statement:
```
Hello I'm building a {{uppercase adjective}} string with Handlebars!
```
In the statement above provided a context of `{adjective: "cool"}` will produce a string of `Hello I'm building a COOL string with Handlebars!`.
Here we can see an example of how string helpers can be used to make a string exactly as we need it. These statements are relatively
simple; we can also stack helpers as such: `{{ uppercase (remove string "bad") }}` with the use of parenthesis.
The other type of statement that can be made with the templating system is conditional ones, that appear as such:
```
Hello I'm building a {{ #gte score "50" }}Great{{ else }}Bad{{ /gte }} string with Handlebars!
```
In this string we can see that the string `Great` or `Bad` will be inserted depending on the state of the
`score` context variable. The comparison, string and array helpers all provide some conditional operators which can be used
in this way. There will also be some operators which will be built with a very similar syntax but will produce an
iterative operation, like a for each - an example of this would be the `forEach` array helper.
## Usage
Usage of this templating package is through one of the primary functions provided by the package - these functions are
as follows:
1. `processString` - `async (string, object)` - given a template string and a context object this will build a string
using our pre-processors, post-processors and handlebars.
2. `processObject` - `async (object, object)` - carries out the functionality provided by `processString` for any string
inside the given object. This will recurse deeply into the provided object so for very large objects this could be slow.
3. `processStringSync` - `(string, object)` - a reduced functionality processing of strings which is synchronous, like
functions provided by Node (e.g. `readdirSync`)
4. `processObjectSync` - `(object, object)` - as with the sync'd string, recurses an object to process it synchronously.
5. `makePropSafe` - `(string)` - some properties cannot be handled by Handlebars, for example `Table 1` is not valid due
to spaces found in the property name. This will update the property name to `[Table 1]` wrapping it in literal
specifiers so that it is safe for use in Handlebars. Ideally this function should be called for every level of an object
being accessed, for example `[Table 1].[property name]` is the syntax that is required for Handlebars.
6. `isValid` - `(string)` - checks the given string for any templates and provides a boolean stating whether it is a valid
template.
## Development
This library is built with [Rollup](https://rollupjs.org/guide/en/) as many of the packages built by Budibase are. We have
built the string templating package as a UMD so that it can be used by Node and Browser based applications. This package also
builds Typescript stubs which when making use of the library will be used by your IDE to provide code completion. The following
commands are provided for development purposes:
1. `yarn build` - will build the Typescript stubs and the bundle into the `dist` directory.
2. `yarn test` - runs the test suite which will check various helpers are still functioning as
expected and a few expected use cases.
3. `yarn dev:builder` - an internal command which is used by lerna to watch and build any changes
to the package as part of the main `yarn dev` of the repo.
It is also important to note this package is managed in the same manner as all other in the mono-repo,
through lerna.

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@ -13,7 +13,7 @@ const EXTERNAL_FUNCTION_COLLECTIONS = [
"number",
"url",
"string",
"markdown",
"comparison",
]
const DATE_NAME = "date"

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@ -2,7 +2,7 @@ const handlebars = require("handlebars")
const { registerAll } = require("./helpers/index")
const processors = require("./processors")
const { cloneDeep } = require("lodash/fp")
const { removeNull } = require("./utilities")
const { removeNull, addConstants } = require("./utilities")
const hbsInstance = handlebars.create()
registerAll(hbsInstance)
@ -82,16 +82,15 @@ module.exports.processObjectSync = (object, context) => {
* @returns {string} The enriched string, all templates should have been replaced if they can be.
*/
module.exports.processStringSync = (string, context) => {
const clonedContext = removeNull(cloneDeep(context))
let clonedContext = removeNull(cloneDeep(context))
clonedContext = addConstants(clonedContext)
// remove any null/undefined properties
if (typeof string !== "string") {
throw "Cannot process non-string types."
}
let template
string = processors.preprocess(string)
// this does not throw an error when template can't be fulfilled, have to try correct beforehand
template = hbsInstance.compile(string)
const template = hbsInstance.compile(string)
return processors.postprocess(template(clonedContext))
}

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@ -1,9 +1,11 @@
const { HelperNames } = require("../helpers")
const { swapStrings, isAlphaNumeric } = require("../utilities")
const FUNCTION_CASES = ["#", "else", "/"]
const PreprocessorNames = {
SWAP_TO_DOT: "swap-to-dot-notation",
HANDLE_SPACES: "handle-spaces-in-properties",
FIX_FUNCTIONS: "fix-functions",
FINALISE: "finalise",
}
@ -37,6 +39,14 @@ module.exports.processors = [
return statement
}),
new Preprocessor(PreprocessorNames.FIX_FUNCTIONS, statement => {
for (let specialCase of FUNCTION_CASES) {
const toFind = `{ ${specialCase}`, replacement = `{${specialCase}`
statement = statement.replace(new RegExp(toFind, "g"), replacement)
}
return statement
}),
new Preprocessor(PreprocessorNames.FINALISE, statement => {
let insideStatement = statement.slice(2, statement.length - 2)
if (insideStatement.charAt(0) === " ") {
@ -46,7 +56,13 @@ module.exports.processors = [
insideStatement = insideStatement.slice(0, insideStatement.length - 1)
}
const possibleHelper = insideStatement.split(" ")[0]
if (HelperNames().some(option => possibleHelper === option)) {
// function helpers can't be wrapped
for (let specialCase of FUNCTION_CASES) {
if (possibleHelper.includes(specialCase)) {
return statement
}
}
if (HelperNames().some(option => possibleHelper.includes(option))) {
insideStatement = `(${insideStatement})`
}
return `{{ all ${insideStatement} }}`

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@ -1,3 +1,4 @@
const _ = require("lodash")
const ALPHA_NUMERIC_REGEX = /^[A-Za-z0-9]+$/g
module.exports.FIND_HBS_REGEX = /{{([^{}])+}}/g
@ -12,12 +13,19 @@ module.exports.swapStrings = (string, start, length, swap) => {
// removes null and undefined
module.exports.removeNull = obj => {
return Object.fromEntries(
Object.entries(obj)
.filter(entry => entry[1] != null)
.map(([key, value]) => [
key,
value === Object(value) ? module.exports.removeNull(value) : value,
])
)
obj = _(obj).omitBy(_.isUndefined).omitBy(_.isNull).value()
for (let [key, value] of Object.entries(obj)) {
// only objects
if (typeof value === "object" && !Array.isArray(value)) {
obj[key] = module.exports.removeNull(value)
}
}
return obj
}
module.exports.addConstants = obj => {
if (obj.now == null) {
obj.now = (new Date()).toISOString()
}
return obj
}

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@ -9,5 +9,253 @@ describe("test the custom helpers we have applied", () => {
})
expect(output).toBe("object is {\"a\":1}")
})
})
describe("test the math helpers", () => {
it("should be able to produce an absolute", async () => {
const output = await processString("{{abs a}}", {
a: -10,
})
expect(parseInt(output)).toBe(10)
})
it("should be able to add", async () => {
const output = await processString("{{add a b}}", {
a: 10,
b: 10,
})
expect(parseInt(output)).toBe(20)
})
it("should be able to average", async () => {
const output = await processString("{{avg a b c}}", {
a: 1,
b: 2,
c: 3,
})
expect(parseInt(output)).toBe(2)
})
})
describe("test the array helpers", () => {
const array = ["hi", "person", "how", "are", "you"]
it("should allow use of the after helper", async () => {
const output = await processString("{{after array 1}}", {
array,
})
expect(output).toBe("person,how,are,you")
})
it("should allow use of the before helper", async () => {
const output = await processString("{{before array 2}}", {
array,
})
expect(output).toBe("hi,person,how")
})
it("should allow use of the filter helper", async () => {
const output = await processString("{{#filter array \"person\"}}THING{{else}}OTHER{{/filter}}", {
array,
})
expect(output).toBe("THING")
})
it("should allow use of the itemAt helper", async () => {
const output = await processString("{{itemAt array 1}}", {
array,
})
expect(output).toBe("person")
})
it("should allow use of the join helper", async () => {
const output = await processString("{{join array \"-\"}}", {
array,
})
expect(output).toBe("hi-person-how-are-you")
})
it("should allow use of the sort helper", async () => {
const output = await processString("{{sort array}}", {
array: ["d", "a", "c", "e"]
})
expect(output).toBe("a,c,d,e")
})
it("should allow use of the unique helper", async () => {
const output = await processString("{{unique array}}", {
array: ["a", "a", "b"]
})
expect(output).toBe("a,b")
})
it("should allow a complex case", async () => {
const output = await processString("{{ last ( sort ( unique array ) ) }}", {
array: ["a", "a", "d", "c", "e"]
})
expect(output).toBe("e")
})
})
describe("test the number helpers", () => {
it("should allow use of the addCommas helper", async () => {
const output = await processString("{{ addCommas number }}", {
number: 10000000
})
expect(output).toBe("10,000,000")
})
it("should allow use of the phoneNumber helper", async () => {
const output = await processString("{{ phoneNumber number }}", {
number: 4490102030,
})
expect(output).toBe("(449) 010-2030")
})
it("should allow use of the toPrecision helper", async () => {
const output = await processString("{{ toPrecision number 2 }}", {
number: 1.222222222,
})
expect(output).toBe("1.2")
})
it("should allow use of the bytes helper", async () => {
const output = await processString("{{ bytes number }}", {
number: 1000000,
})
expect(output).toBe("1 MB")
})
})
describe("test the url helpers", () => {
const url = "http://example.com?query=1"
it("should allow use of the stripQueryString helper", async () => {
const output = await processString('{{stripQuerystring url }}', {
url,
})
expect(output).toBe("http://example.com")
})
it("should allow use of the stripProtocol helper", async () => {
const output = await processString("{{ stripProtocol url }}", {
url,
})
expect(output).toBe("//example.com/?query=1")
})
it("should allow use of the urlParse helper", async () => {
const output = await processString("{{ object ( urlParse url ) }}", {
url,
})
expect(output).toBe("{\"protocol\":\"http:\",\"slashes\":true,\"auth\":null,\"host\":\"example.com\"," +
"\"port\":null,\"hostname\":\"example.com\",\"hash\":null,\"search\":\"?query=1\"," +
"\"query\":\"query=1\",\"pathname\":\"/\",\"path\":\"/?query=1\"," +
"\"href\":\"http://example.com/?query=1\"}")
})
})
describe("test the date helpers", () => {
it("should allow use of the date helper", async () => {
const date = new Date(1611577535000)
const output = await processString("{{ date time 'YYYY-MM-DD' }}", {
time: date.toISOString(),
})
expect(output).toBe("2021-01-25")
})
it("should allow use of the date helper with now time", async () => {
const date = new Date()
const output = await processString("{{ date now 'DD' }}", {})
expect(output).toBe(date.getDate().toString())
})
})
describe("test the string helpers", () => {
it("should allow use of the append helper", async () => {
const output = await processString("{{ append filename '.txt' }}", {
filename: "yummy",
})
expect(output).toBe("yummy.txt")
})
it("should allow use of the camelcase helper", async () => {
const output = await processString("{{ camelcase camel }}", {
camel: "testing this thing",
})
expect(output).toBe("testingThisThing")
})
it("should allow use of the capitalize helper", async () => {
const output = await processString("{{ capitalize string }}", {
string: "this is a string",
})
expect(output).toBe("This is a string")
})
it("should allow use of the capitalizeAll helper", async () => {
const output = await processString("{{ capitalizeAll string }}", {
string: "this is a string",
})
expect(output).toBe("This Is A String")
})
it("should allow use of the replace helper", async () => {
const output = await processString("{{ replace string 'Mike' name }}", {
string: "Hello my name is Mike",
name: "David",
})
expect(output).toBe("Hello my name is David")
})
it("should allow use of the split helper", async () => {
const output = await processString("{{ first ( split string ' ' ) }}", {
string: "this is a string",
})
expect(output).toBe("this")
})
it("should allow use of the remove helper", async () => {
const output = await processString("{{ remove string 'string' }}", {
string: "this is a string",
})
expect(output).toBe("this is a ")
})
it("should allow use of the startsWith helper", async () => {
const output = await processString("{{ #startsWith 'Hello' string }}Hi!{{ else }}Goodbye!{{ /startsWith }}", {
string: "Hello my name is Mike",
})
expect(output).toBe("Hi!")
})
})
describe("test the comparison helpers", () => {
async function compare(func, a, b) {
const output = await processString(`{{ #${func} a b }}Success{{ else }}Fail{{ /${func} }}`, {
a,
b,
})
expect(output).toBe("Success")
}
it("should allow use of the lt helper", async () => {
await compare("lt", 10, 15)
})
it("should allow use of the gt helper", async () => {
await compare("gt", 15, 10)
})
it("should allow use of the and helper", async () => {
await compare("and", true, true)
})
it("should allow use of the or helper", async () => {
await compare("or", false, true)
})
it("should allow use of gte with a literal value", async () => {
const output = await processString(`{{ #gte a "50" }}s{{ else }}f{{ /gte }}`, {
a: 51,
})
expect(output).toBe("s")
})
})