feast/src/game/interface.ts

export interface LogEntry {
    render: () => HTMLElement[];
}

export class LogLines implements LogEntry {
    lines: string[]

    constructor (...lines: string[]) {
      this.lines = lines
    }

    render (): HTMLElement[] {
      const p = document.createElement('p')
      this.lines.forEach(line => {
        const div = document.createElement('div')
        div.innerText = line
        p.appendChild(div)
      })

      return [p]
    }
}

export class CompositeLog implements LogEntry {
    entries: LogEntry[]

    constructor (...entries: LogEntry[]) {
      this.entries = entries
    }

    render (): HTMLElement[] {
      return this.entries.map(entry => entry.render()).reduce((results: HTMLElement[], next: HTMLElement[]) => results.concat(next), [])
    }
}

export function log (entry: LogEntry): void {
  entry.render().forEach(elem => document.querySelector('#log')?.appendChild(elem))
}