Japanese Text Breaks Your App in 7 Quiet Ways (With Code)
Your app passes every test in English. Then a Japanese user types their name, presses Enter, and the form submits half a word. Japanese text breaks a lot of quiet assumptions: that words have spaces, that length counts characters, that Enter means "send", that sorting by string sorts by sound. None of these show up as errors. They just make the app feel slightly broken to Japanese users. I'm a…
Japanese text can break your application in numerous subtle ways. When a Japanese user inputs data, unexpected issues can arise, often unnoticed by developers who have not tested their applications with Japanese text. Here are the seven most common problems, along with code snippets to help fix them.
1. Enter Key Sends Partial Text During IME Input: Japanese characters are entered through an Input Method Editor (IME). Users type a word like kaigi (会議 meaning meeting), press space to convert it, and then press Enter to confirm. If your application sends data on Enter keypress, it may send an incomplete version of the text, commonly seen in chat apps or search fields. To prevent this, listen for the keydown event and ignore Enter if the IME is converting text.
2. length Doesn't Count Characters Accurately: In JavaScript, text.length counts Unicode code points, not characters. Japanese text includes characters like 𠮷 that count as two code points but still represent a single character. Additionally, emoji with skin tone modifiers count as multiple code points. To properly handle character counting, use the Intl.Segmenter API to get grapheme clusters (individual visual characters) instead of code points.
3. Line Breaks and No Spaces: Japanese text lacks spaces between words, which can cause browsers to break lines between any two characters, even in the middle of a word. Two CSS properties can help: line-break: strict; to avoid starting a line with certain characters and word-break: auto-phrase; for better line breaks in Japanese text. However, these only work when the element is marked with lang="ja" and may not work in all browsers, so it's essential to keep text lengths short and test on various devices.
4. Sentence Construction and Word Order: Japanese and English structures differ significantly. In Japanese, the verb usually comes at the end of the sentence. Ambiguities in translating these differences can lead to misunderstandings. When building sentences, provide the translator with the full sentence and use placeholders for dynamic content. Also, consider that plural forms are simpler in Japanese ("other") compared to English.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
