39 lines
1.2 KiB
TypeScript
39 lines
1.2 KiB
TypeScript
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/**
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* Checks if the object contains only valid types.
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*/
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function isValidFrontmatterObject(obj: Record<string, any>): boolean {
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return Object.values(obj).every(
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(value) =>
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value == null || // null or undefined
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typeof value === "string" ||
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typeof value === "boolean" ||
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typeof value === "number" ||
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(Array.isArray(value) && value.every((item) => typeof item === "string")), // valid string array
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);
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}
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/**
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* Converts a valid object into YAML-like frontmatter string.
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* Throws error if object contains invalid types.
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*/
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export function stringifyFrontmatter(obj: Record<string, any>): string {
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if (!isValidFrontmatterObject(obj)) {
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throw new Error("Invalid frontmatter");
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}
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return `---\n${Object.entries(obj)
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.map(([key, value]) => {
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if (value == null) {
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return `${key}: null`; // Handle null values explicitly
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}
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if (Array.isArray(value)) {
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return `${key}: ${JSON.stringify(value)}`; // Handle arrays
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}
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if (typeof value === "string") {
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return `${key}: ${JSON.stringify(value)}`; // Wrap strings with quotes
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}
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return `${key}: ${value}`; // Handle numbers and booleans
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})
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.join("\n")}\n---`;
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}
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