161 lines
6.1 KiB
JavaScript
161 lines
6.1 KiB
JavaScript
const handlebars = require("handlebars")
|
|
const { registerAll } = require("./helpers/index")
|
|
const processors = require("./processors")
|
|
const { removeHandlebarsStatements } = require("./utilities")
|
|
const manifest = require("../manifest.json")
|
|
|
|
const hbsInstance = handlebars.create()
|
|
registerAll(hbsInstance)
|
|
|
|
/**
|
|
* utility function to check if the object is valid
|
|
*/
|
|
function testObject(object) {
|
|
// JSON stringify will fail if there are any cycles, stops infinite recursion
|
|
try {
|
|
JSON.stringify(object)
|
|
} catch (err) {
|
|
throw "Unable to process inputs to JSON, cannot recurse"
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Given an input object this will recurse through all props to try and update any handlebars statements within.
|
|
* @param {object|array} object The input structure which is to be recursed, it is important to note that
|
|
* if the structure contains any cycles then this will fail.
|
|
* @param {object} context The context that handlebars should fill data from.
|
|
* @returns {Promise<object|array>} The structure input, as fully updated as possible.
|
|
*/
|
|
module.exports.processObject = async (object, context) => {
|
|
testObject(object)
|
|
for (let key of Object.keys(object || {})) {
|
|
if (object[key] != null) {
|
|
let val = object[key]
|
|
if (typeof val === "string") {
|
|
object[key] = await module.exports.processString(object[key], context)
|
|
} else if (typeof val === "object") {
|
|
object[key] = await module.exports.processObject(object[key], context)
|
|
}
|
|
}
|
|
}
|
|
return object
|
|
}
|
|
|
|
/**
|
|
* This will process a single handlebars containing string. If the string passed in has no valid handlebars statements
|
|
* then nothing will occur.
|
|
* @param {string} string The template string which is the filled from the context object.
|
|
* @param {object} context An object of information which will be used to enrich the string.
|
|
* @returns {Promise<string>} The enriched string, all templates should have been replaced if they can be.
|
|
*/
|
|
module.exports.processString = async (string, context) => {
|
|
// TODO: carry out any async calls before carrying out async call
|
|
return module.exports.processStringSync(string, context)
|
|
}
|
|
|
|
/**
|
|
* Given an input object this will recurse through all props to try and update any handlebars statements within. This is
|
|
* a pure sync call and therefore does not have the full functionality of the async call.
|
|
* @param {object|array} object The input structure which is to be recursed, it is important to note that
|
|
* if the structure contains any cycles then this will fail.
|
|
* @param {object} context The context that handlebars should fill data from.
|
|
* @returns {object|array} The structure input, as fully updated as possible.
|
|
*/
|
|
module.exports.processObjectSync = (object, context) => {
|
|
testObject(object)
|
|
for (let key of Object.keys(object || {})) {
|
|
let val = object[key]
|
|
if (typeof val === "string") {
|
|
object[key] = module.exports.processStringSync(object[key], context)
|
|
} else if (typeof val === "object") {
|
|
object[key] = module.exports.processObjectSync(object[key], context)
|
|
}
|
|
}
|
|
return object
|
|
}
|
|
|
|
/**
|
|
* This will process a single handlebars containing string. If the string passed in has no valid handlebars statements
|
|
* then nothing will occur. This is a pure sync call and therefore does not have the full functionality of the async call.
|
|
* @param {string} string The template string which is the filled from the context object.
|
|
* @param {object} context An object of information which will be used to enrich the string.
|
|
* @returns {string} The enriched string, all templates should have been replaced if they can be.
|
|
*/
|
|
module.exports.processStringSync = (string, context) => {
|
|
if (!exports.isValid(string)) {
|
|
return string
|
|
}
|
|
// take a copy of input incase error
|
|
const input = string
|
|
if (typeof string !== "string") {
|
|
throw "Cannot process non-string types."
|
|
}
|
|
try {
|
|
string = processors.preprocess(string)
|
|
// this does not throw an error when template can't be fulfilled, have to try correct beforehand
|
|
const template = hbsInstance.compile(string, {
|
|
strict: false,
|
|
})
|
|
return processors.postprocess(template({
|
|
now: new Date().toISOString(),
|
|
...context,
|
|
}))
|
|
} catch (err) {
|
|
return removeHandlebarsStatements(input)
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Simple utility function which makes sure that a templating property has been wrapped in literal specifiers correctly.
|
|
* @param {string} property The property which is to be wrapped.
|
|
* @returns {string} The wrapped property ready to be added to a templating string.
|
|
*/
|
|
module.exports.makePropSafe = property => {
|
|
return `[${property}]`.replace("[[", "[").replace("]]", "]")
|
|
}
|
|
|
|
/**
|
|
* Checks whether or not a template string contains totally valid syntax (simply tries running it)
|
|
* @param string The string to test for valid syntax - this may contain no templates and will be considered valid.
|
|
* @returns {boolean} Whether or not the input string is valid.
|
|
*/
|
|
module.exports.isValid = string => {
|
|
const validCases = [
|
|
"string",
|
|
"number",
|
|
"object",
|
|
"array",
|
|
"cannot read property",
|
|
"undefined",
|
|
]
|
|
// this is a portion of a specific string always output by handlebars in the case of a syntax error
|
|
const invalidCases = [`expecting '`]
|
|
// don't really need a real context to check if its valid
|
|
const context = {}
|
|
try {
|
|
hbsInstance.compile(processors.preprocess(string, false))(context)
|
|
return true
|
|
} catch (err) {
|
|
const msg = err && err.message ? err.message : err
|
|
if (!msg) {
|
|
return false
|
|
}
|
|
const invalidCase = invalidCases.some(invalidCase =>
|
|
msg.toLowerCase().includes(invalidCase)
|
|
)
|
|
const validCase = validCases.some(validCase =>
|
|
msg.toLowerCase().includes(validCase)
|
|
)
|
|
// special case for maths functions - don't have inputs yet
|
|
return validCase && !invalidCase
|
|
}
|
|
}
|
|
|
|
/**
|
|
* We have generated a static manifest file from the helpers that this string templating package makes use of.
|
|
* This manifest provides information about each of the helpers and how it can be used.
|
|
* @returns The manifest JSON which has been generated from the helpers.
|
|
*/
|
|
module.exports.getManifest = () => {
|
|
return manifest
|
|
}
|