budibase/packages/string-templates/src/helpers/javascript.ts

101 lines
3.1 KiB
TypeScript

import { atob, isJSAllowed } from "../utilities"
import cloneDeep from "lodash/fp/cloneDeep"
import { LITERAL_MARKER } from "../helpers/constants"
import { getJsHelperList } from "./list"
import { iifeWrapper } from "../iife"
// The method of executing JS scripts depends on the bundle being built.
// This setter is used in the entrypoint (either index.js or index.mjs).
let runJS: ((js: string, context: any) => any) | undefined = undefined
export const setJSRunner = (runner: typeof runJS) => (runJS = runner)
export const removeJSRunner = () => {
runJS = undefined
}
let onErrorLog: (message: Error) => void
export const setOnErrorLog = (delegate: typeof onErrorLog) =>
(onErrorLog = delegate)
// Helper utility to strip square brackets from a value
const removeSquareBrackets = (value: string) => {
if (!value || typeof value !== "string") {
return value
}
const regex = /\[+(.+)]+/
const matches = value.match(regex)
if (matches && matches[1]) {
return matches[1]
}
return value
}
// Our context getter function provided to JS code as $.
// Extracts a value from context.
const getContextValue = (path: string, context: any) => {
let data = context
path.split(".").forEach(key => {
if (data == null || typeof data !== "object") {
return null
}
data = data[removeSquareBrackets(key)]
})
return data
}
// Evaluates JS code against a certain context
export function processJS(handlebars: string, context: any) {
if (!isJSAllowed() || !runJS) {
throw new Error("JS disabled in environment.")
}
try {
// Wrap JS in a function and immediately invoke it.
// This is required to allow the final `return` statement to be valid.
const js = iifeWrapper(atob(handlebars))
// Transform snippets into an object for faster access, and cache previously
// evaluated snippets
let snippetMap: any = {}
let snippetCache: any = {}
for (let snippet of context.snippets || []) {
snippetMap[snippet.name] = snippet.code
}
// Our $ context function gets a value from context.
// We clone the context to avoid mutation in the binding affecting real
// app context.
const clonedContext = cloneDeep({ ...context, snippets: null })
const sandboxContext = {
$: (path: string) => getContextValue(path, clonedContext),
helpers: getJsHelperList(),
// Proxy to evaluate snippets when running in the browser
snippets: new Proxy(
{},
{
get: function (_, name) {
if (!(name in snippetCache)) {
snippetCache[name] = eval(iifeWrapper(snippetMap[name]))
}
return snippetCache[name]
},
}
),
}
// Create a sandbox with our context and run the JS
const res = { data: runJS(js, sandboxContext) }
return `{{${LITERAL_MARKER} js_result-${JSON.stringify(res)}}}`
} catch (error: any) {
onErrorLog && onErrorLog(error)
if (error.code === "ERR_SCRIPT_EXECUTION_TIMEOUT") {
return "Timed out while executing JS"
}
if (error.name === "ExecutionTimeoutError") {
return "Request JS execution limit hit"
}
return "Error while executing JS"
}
}