61 lines
2.4 KiB
JavaScript
61 lines
2.4 KiB
JavaScript
// objAsString will try to return the provided object as a string. If the
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// object is already a string, it will be returned without modification. If the
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// object is an 'Error', the message of the error will be returned. If the object
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// has a toString method, the toString method will be called and the result
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// will be returned. If the object is null or undefined, a special string will
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// be returned indicating that the undefined/null object cannot be converted to
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// a string. In all other cases, JSON.stringify is used. If JSON.stringify
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// throws an exception, a message "[could not provide object as string]" will
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// be returned.
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//
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// NOTE: objAsString is intended to produce human readable output. It is lossy,
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// and it is not intended to be used for serialization.
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function objAsString(obj) {
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// Check for undefined input.
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if (obj === undefined) {
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return "[cannot convert undefined to string]";
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}
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if (obj === null) {
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return "[cannot convert null to string]";
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}
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// Parse the error into a string.
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if (typeof obj === "string") {
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return obj;
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}
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// Check if the object is an error, and return the message of the error if
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// so.
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if (obj instanceof Error) {
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return obj.message;
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}
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// Check if the object has a 'toString' method defined on it. To ensure
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// that we don't crash or throw, check that the toString is a function, and
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// also that the return value of toString is a string.
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if (Object.prototype.hasOwnProperty.call(obj, "toString")) {
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if (typeof obj.toString === "function") {
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const str = obj.toString();
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if (typeof str === "string") {
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return str;
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}
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}
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}
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// If the object does not have a custom toString, attempt to perform a
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// JSON.stringify. We use a lot of bigints in libskynet, and calling
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// JSON.stringify on an object with a bigint will cause a throw, so we add
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// some custom handling to allow bigint objects to still be encoded.
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try {
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return JSON.stringify(obj, (_, v) => {
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if (typeof v === "bigint") {
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return v.toString();
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}
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return v;
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});
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}
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catch (err) {
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if (err !== undefined && typeof err.message === "string") {
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return `[stringify failed]: ${err.message}`;
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}
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return "[stringify failed]";
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}
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}
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export { objAsString };
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