wasm-binding.ts

import init, { Resvg as _Resvg, InitInput } from './wasm/dist'
import { CustomFontsOptions, ResvgRenderOptions, SystemFontsOptions } from './wasm/index'

let initialized = false

/**
 * Initialize Wasm module
 * @param module_or_path WebAssembly Module or .wasm url
 *
 */
export const initWasm = async (module_or_path: Promise<InitInput> | InitInput): Promise<void> => {
  if (initialized) {
    throw new Error('Already initialized. The `initWasm()` function can be used only once.')
  }
  await init(await module_or_path)
  initialized = true
}

export const Resvg = class extends _Resvg {
  /**
   * @param {Uint8Array | string} svg
   * @param {ResvgRenderOptions | undefined} options
   */
  constructor(svg: Uint8Array | string, options?: ResvgRenderOptions) {
    if (!initialized) throw new Error('Wasm has not been initialized. Call `initWasm()` function.')

    const font = options?.font

    if (!!font && isCustomFontsOptions(font)) {
      const serializableOptions = {
        ...options,
        font: {
          ...font,
          fontBuffers: undefined,
        },
      }

      super(svg, JSON.stringify(serializableOptions), font.fontBuffers)
    } else {
      super(svg, JSON.stringify(options))
    }
  }
}

function isCustomFontsOptions(value: SystemFontsOptions | CustomFontsOptions): value is CustomFontsOptions {
  return Object.prototype.hasOwnProperty.call(value, 'fontBuffers')
}