import {z} from 'zod';
const FIELD_CHARS = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_$';
const FIELD_START_CHARS = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_$';
const isFieldName = (name: string) => {
if (name.length === 0) {
return false;
}
return (
FIELD_START_CHARS.includes(name[0]) && [...name].every((c: string) => FIELD_CHARS.includes(c))
);
};
const displayPath = (path: PropertyKey[] | undefined) => {
if (!path || path.length === 0) {
return '(root)';
}
let display = `${String(path[0])}`;
for (const part of path.slice(1)) {
if (typeof part === 'number') {
display += `[${part}]`;
} else if (typeof part === 'string' && isFieldName(part)) {
display += `.${part}`;
} else {
display += `["${String(part)}"]`;
}
}
return display;
};
const getTypeName = (value: unknown): string => {
if (value === null) return 'null';
if (value === undefined) return 'undefined';
if (Array.isArray(value)) return 'array';
return typeof value;
};
const formatUnionError = (errors: z.core.$ZodIssue[][], input: unknown) => {
// In Zod v4, errors is an array of arrays of issues
const allIssues = errors.flat();
const invalidTypeIssues = allIssues.filter(
(i): i is z.core.$ZodIssueInvalidType => i.code === 'invalid_type',
);
if (invalidTypeIssues.length === 0) {
return 'Invalid union value';
}
const expectedTypes = invalidTypeIssues.map((i) => i.expected).join(' | ');
const receivedType = getTypeName(input);
return `Expected ${expectedTypes}, received ${receivedType}`;
};
export const errorMap: z.core.$ZodErrorMap = (issue) => {
let message: string | undefined;
if (issue.code === 'invalid_type') {
const received = issue.received ?? getTypeName(issue.input);
message = `Expected ${issue.expected}, received ${received}`;
} else if (issue.code === 'invalid_value') {
const values = issue.values as unknown[];
message = `Expected ${values.map((o) => `"${o}"`).join(' | ')}`;
} else if (issue.code === 'unrecognized_keys') {
const keys = issue.keys ?? [];
message =
`Unrecognized key${keys.length === 1 ? '' : 's'}: ` +
`${keys.map((k) => `"${k}"`).join(', ')}`;
} else if (issue.code === 'invalid_union') {
message = formatUnionError(issue.errors, issue.input);
} else {
message = issue.message;
}
if (!message) {
return undefined; // Let Zod use the default message
}
return `${displayPath(issue.path)}: ${message}`;
};
