Typescript used to generate a Netlify CMS config.yml

config.src.ts

// See https://www.marcveens.nl/netlify-cms-generate-config-yml

import { NetlifyCmsConfig, NetlifyCmsCollection, NetlifyCmsField } from './types/NetlifyCmsConfig';
import * as YAML from 'yaml';
import * as fs from 'fs';
import * as path from 'path';

const defaultMetaFields: NetlifyCmsField[] = [
    { label: 'Title', name: 'title', widget: 'string' },
    { label: 'Page URL', name: 'url', widget: 'string' },
    {
        label: 'Meta', name: 'meta', widget: 'object', fields: [
            { label: 'Title', name: 'title', widget: 'string' },
            { label: 'Description', name: 'description', widget: 'string' }
        ]
    }
];

const demoPage: NetlifyCmsCollection = {
    name: 'demopage',
    label: 'Demo page',
    folder: 'src/pages/demopage',
    create: true,
    delete: true,
    extension: 'md',
    slug: '{{url}}',
    fields: [
        { label: 'Template Key', name: 'templateKey', widget: 'hidden', default: 'demoPage' },
        ...defaultMetaFields,
        { label: 'Body', name: 'body', widget: 'markdown' },
    ]
};

const config: NetlifyCmsConfig = {
    backend: {
        name: 'git-gateway',
        branch: 'master'
    },
    media_folder: 'static/img',
    public_folder: '/img',
    publish_mode: 'editorial_workflow',
    logo_url: 'https://example.com/logo.png',
    collections: [
        demoPage
    ]
};

// To generate the end file
const configDisclaimer = '# This file is generated\n# Only edit the config.src.ts file\n\n'; 
const configString = `${configDisclaimer}${YAML.stringify(config)}`;

fs.writeFile(path.resolve(__dirname, 'config.yml'), configString, (err) => {
    if (err) console.log(err);
    console.log('Generated the config.yml');
});

NetlifyCmsConfig.ts

// See https://www.marcveens.nl/netlify-cms-generate-config-yml
// https://www.netlifycms.org/docs/configuration-options/

type PublishMode = 'simple' | 'editorial_workflow';
type ExtensionType = 'yml' | 'yaml' | 'toml' | 'json' | 'md' | 'markdown' | 'html';
type FormatType = 'yml' | 'yaml' | 'toml' | 'json' | 'frontmatter' | 'yaml-frontmatter' | 'toml-frontmatter' | 'json-frontmatter';
type WidgetType = 'boolean' | 'date' | 'datetime' | 'file' | 'hidden' | 'image'
                    | 'list' | 'map' | 'markdown' | 'number' | 'object' | 'relation'
                    | 'select' | 'string' | 'text' | string;
type MapType = 'Point' | 'LineString' | 'Polygon';     
type MarkdownButtonType = 'bold' | 'italic' | 'code' | 'link' | 'heading-one' | 'heading-two'
                    | 'quote' | 'code-block' | 'bulleted-list' | 'numbered-list';               
type ValueType = 'int' | 'float';

export type NetlifyCmsField = {
    name: string;
    label?: string;
    widget: WidgetType;
    default?: string | string[] | number;
    required?: boolean;
    hint?: string;
    pattern?: string;
    
    // date | datetime
    format?: string;
    dateFormat?: boolean | string;
    timeFormat?: boolean | string;

    // file | image
    media_library?: {
        config: {
            multiple?: boolean;
        }
    };

    // list | object
    allow_add?: boolean;
    field?: NetlifyCmsField;
    fields?: NetlifyCmsField[]; // actually required in case of object

    // map
    type?: MapType;

    // markdown
    buttons?: MarkdownButtonType[];

    // number
    valueType?: ValueType | string;
    min?: number;
    max?: number;
    step?: number;

    // relation
    collection?: string;
    displayFields?: string[];
    searchFields?: string;
    valueField?: string;
    multiple?: boolean;

    // select
    options?: string[] | { label: string, value: string }[];
};

export type NetlifyCmsCollection = {
    name: string;
    identifier_field?: string; 
    label?: string;
    label_singular?: string;
    description?: string;
    files?: string;
    folder?: string;
    filter?: string;
    create?: boolean;
    delete?: boolean;
    extension?: ExtensionType;
    format?: FormatType;
    frontmatter_delimiter?: string | string[];
    slug?: string;
    preview_path?: string;
    fields: NetlifyCmsField[]; 
    editor?: boolean;
    summary?: string;
}

export type NetlifyCmsConfig = {
    backend: {
        name: string;
        repo?: string;
        accept_roles?: string[];
        branch?: string;
        api_root?: string;
        site_domain?: string;
        base_url?: string;
        auth_endpoint?: string;
    };

    publish_mode?: PublishMode;

    media_folder: string;
    public_folder?: string;
    media_library?: {
        name: string;
        config?: {
            publicKey?: string;
        }
    };

    site_url?: string;
    display_url?: string;
    logo_url?: string;
    show_preview_links?: boolean;
    slug?: {
        encoding?: string;
        clean_accents?: boolean;
        sanitize_replacement?: string;
    };

    collections: NetlifyCmsCollection[];
}

package.json

{
  "scripts": {
    "generate-config-yml": "ts-node static/admin/config.src.ts"
  }
}

Hey thanks, you already made what i was looking for!

Meaby we could upload it to npm or on https://github.com/DefinitelyTyped/DefinitelyTyped