template-nestjs-generator/src/handlebars-config.ts

A custom NestJS CRUD generator

import * as Handlebars from "handlebars"

export function configHandlebars() {
    Handlebars.registerHelper("toLowerCase", function (value) {
        return value && typeof value === "string" ? value.toLowerCase() : ""
    })
    Handlebars.registerHelper("newLine", () => "\n")

    // Helper para negación
    Handlebars.registerHelper("not", function (value) {
        return !value
    })

    // Helper para condicional 'or'
    Handlebars.registerHelper("or", function (value1, value2) {
        return value1 || value2
    })

    // Helper para stringify
    Handlebars.registerHelper("json", function (context) {
        return JSON.stringify(context)
    })

    Handlebars.registerHelper(
        "checkRequired",
        function (
            this: any,
            isRequired: any,
            options: Handlebars.HelperOptions
        ) {
            if (isRequired && isRequired !== undefined && isRequired !== null) {
                return options.fn(this)
            } else {
                return options.inverse(this)
            }
        }
    )

    Handlebars.registerHelper(
        "ifDefined",
        function (this: any, value: any, options: Handlebars.HelperOptions) {
            if (value !== undefined && value !== null) {
                return options.fn(this)
            } else {
                return options.inverse(this)
            }
        }
    )

    Handlebars.registerHelper("typeValidator", function (type) {
        switch (type) {
            case "string":
                return "@IsString()"
            case "number":
                return "@IsNumber()"
            case "boolean":
                return "@IsBoolean()"
            case "Date":
                return "@Type(() => Date) @IsDate()"
            default:
                return ""
        }
    })

    Handlebars.registerHelper("quoteIfString", function (value: any) {
        if (typeof value === "string") {
            return `"${value}"`
        }
        return value
    })

    Handlebars.registerHelper(
        "importValidators",
        function (properties, options) {
            const validators = new Set()
            properties?.forEach((prop: { validators: string[] }) => {
                prop.validators?.forEach((validator) => {
                    validators?.add(validator)
                })
            })
            return Array?.from(validators)
                ?.map(
                    (validator) =>
                        `import { ${validator} } from 'class-validator';`
                )
                ?.join("\n")
        }
    )
}