code.ts

/**
 Copyright 2023 LINE Corporation

 LINE Corporation licenses this file to you under the Apache License,
 version 2.0 (the "License"); you may not use this file except in compliance
 with the License. You may obtain a copy of the License at:

 https://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 License for the specific language governing permissions and limitations
 under the License.
 **/

figma.showUI(__html__, {width: 340, height: 411});

(async () => {
    // select last selected from/to language
    figma.ui.postMessage({type: 'fromLanguage', value: await figma.clientStorage.getAsync('fromLanguage')})
    figma.ui.postMessage({type: 'toLanguage', value: await figma.clientStorage.getAsync('toLanguage')})
})()

figma.ui.onmessage = async msg => {
    // translating selection in figma
    if (msg.type === 'translate') {
        const selection = figma.currentPage.selection
        for (const node of selection) {
            resolveChildren(node, msg)
        }
    }

    // save last selected from language
    if (msg.type === 'updateFromLanguage') {
        figma.clientStorage.setAsync('fromLanguage', msg.value)
    }

    // save last selected to language
    if (msg.type === 'updateToLanguage') {
        figma.clientStorage.setAsync('toLanguage', msg.value)
    }
}

async function resolveChildren(node: SceneNode, msg: any) {
    if (node.type === 'TEXT') {
        const text = node.characters
        if (isContainCharacter(text)) {
            await figma.loadFontAsync(node.fontName as FontName)
            node.characters = await translate(text, msg.source, msg.target)
        }
    }
    if ('children' in node) {
        for (const children of node.children) {
            resolveChildren(children, msg)
        }
    }
}

function isContainCharacter(text: string) {
    return /[^0-9 ]/gi.test(text)
}

async function translate(text: string, source: string, target: string): Promise<string> {
    const translated = text // call your translator api
    return translated
}