How to fix invalid stage name: stage name cannot start with a number in Docker

FROM node:18 AS 1builder
FROM golang:1.21 AS 2nd-stage
FROM python:3.11 AS 3build

docker build --progress=plain -t myapp .

FROM node:18 AS 1builder
WORKDIR /app
COPY package*.json ./
RUN npm install

FROM node:18 AS builder
WORKDIR /app
COPY package*.json ./
RUN npm install

FROM node:18 AS stage-one
# or
FROM node:18 AS first-builder

# Stage 1: Build
FROM node:18 AS builder
WORKDIR /app
COPY . .
RUN npm ci && npm run build

# Stage 2: Runtime
FROM nginx:alpine AS runtime
# Update the --from reference to match the new stage name
COPY --from=builder /app/dist /usr/share/nginx/html

FROM node:18 AS builder
FROM node:18 AS build_stage
FROM node:18 AS build-stage
FROM node:18 AS stage1        # Number at end is OK
FROM node:18 AS build.v2      # Period is OK

FROM node:18 AS 1builder      # Starts with number
FROM node:18 AS build@stage   # Contains @
FROM node:18 AS build#1       # Contains #
FROM node:18 AS -builder      # Starts with hyphen

ARG VERSION=2
FROM node:18 AS ${VERSION}builder
# Resolves to "2builder" - invalid!

ARG VERSION=2
FROM node:18 AS builder-v${VERSION}
# Resolves to "builder-v2" - valid!

ARG STAGE_NAME=stage1
FROM node:18 AS build-${STAGE_NAME}

# Recommended: lowercase
FROM node:18 AS builder
FROM nginx:alpine
COPY --from=builder /app/dist /usr/share/nginx/html

# Works but may cause issues with BuildKit
FROM node:18 AS Builder
FROM nginx:alpine
# BuildKit requires lowercase reference even if defined uppercase
COPY --from=builder /app/dist /usr/share/nginx/html