Shorten subject names to prefix before hyphen for charts and standards

[alvin000009238]

Motivation

• Consistently shorten long subject labels by keeping only the text before - so elective names like 選修物理-力學二與熱學 display as 選修物理 and 選修化學-物質構造與反應速率 display as 選修化學 in all UI places that show subject names.

Description

• Replaced the mapping-based shortenName in frontend/dashboard.js with a function that first cleans <br/> then returns the substring before the first - (shortenName(name)).
• The charts in frontend/charts.js (personal vs. class average and score comparison) and the class standards table in frontend/dashboard.js now automatically use the updated shortenName behavior.
• Updated tests/frontend/dashboard.test.js to validate the new behavior for hyphenated elective names and to ensure names without - remain unchanged.

Testing

• Ran npm test and all frontend tests passed (all tests green).
• The updated unit tests in tests/frontend/dashboard.test.js verify 選修物理-力學二與熱學 -> 選修物理, 選修化學-物質構造與反應速率 -> 選修化學, and unchanged output for names without a hyphen.

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Codex Task

[gemini-code-assist]

Code Review

This pull request refactors the shortenName function to use hyphen-based splitting for subject names instead of a hardcoded map. Feedback indicates a bug in null handling where null values are converted to the string 'null', and a regression where specific manual mappings for subjects like '英語文' were removed, leading to longer labels in the UI. A suggestion was provided to restore these mappings and improve input validation.

[gemini-code-assist]

The updated shortenName function introduces two issues:

1. Null Handling: If name is null, String(name) returns the string 'null', which is then processed and returned. The previous implementation correctly returned null (which escapeHTML handles as an empty string). Using a truthiness check or explicit null check is safer.
2. Shortening Regression: The manual mappings for '英語文' -> '英文' and '公民與社會' -> '公民' were removed. This results in these subject names appearing longer in the UI, which contradicts the primary goal of shortening subject labels for better display in charts and tables.

Consider restoring these specific mappings and adding a robust null check.

export function shortenName(name) {
    if (!name) return '';
    const cleanedName = cleanSubjectName(String(name));
    const [baseName] = cleanedName.split('-');
    const result = baseName.trim() || cleanedName;

    // Maintain manual mappings for subjects that don't follow the hyphen pattern
    const manualMappings = {
        '英語文': '英文',
        '公民與社會': '公民'
    };
    return manualMappings[result] || result;
}

[Copilot]

Pull request overview

This PR updates how subject names are shortened across the frontend so hyphenated elective subject labels display using only the prefix before the first -, improving consistency in charts and standards displays.

Changes:

• Replaced the mapping-based shortenName with logic that cleans subject names and returns the text before the first -.
• Updated frontend tests to validate the new hyphen-prefix shortening behavior and ensure non-hyphenated names remain unchanged.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
frontend/dashboard.js	Reworks shortenName to derive the shortened label from the pre-hyphen prefix after cleaning.
tests/frontend/dashboard.test.js	Updates unit tests to reflect the new shortenName behavior for hyphenated vs. non-hyphenated names.

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[Copilot]

shortenName currently does String(name), so shortenName(null) becomes the literal string 'null' (and undefined becomes 'undefined'). Since SubjectName comes from the backend via subject.get('SubjectName'), null values are possible and would display incorrectly in the UI. Consider normalizing with String(name ?? '') (or returning '' for nullish values) before cleaning/splitting.

Suggested change

	export function shortenName(name = '') {
	const cleanedName = cleanSubjectName(String(name));
	export function shortenName(name) {
	const normalizedName = name ?? '';
	const cleanedName = cleanSubjectName(String(normalizedName));

[Copilot]

The updated shortenName behavior includes cleaning <br/> (via cleanSubjectName) and new handling for non-string inputs (default param). The tests only cover hyphen splitting for normal strings; please add coverage for a name containing <br/> and for nullish inputs (e.g., null/undefined) to prevent regressions and to lock in the intended output.

Suggested change

	});
	});
	it('should clean <br/> tags before shortening', () => {
	assert.equal(shortenName('選修化學<br/>-物質構造與反應速率'), '選修化學');
	assert.equal(shortenName('英語文<br/>'), '英語文');
	});
	it('should handle nullish inputs using the default value', () => {
	assert.equal(shortenName(), '');
	assert.equal(shortenName(undefined), '');
	assert.equal(shortenName(null), '');
	});