git ssb

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/**
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 * Module exports.
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 */
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module.exports = deprecate;
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/**
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 * Mark that a method should not be used.
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 * Returns a modified function which warns once by default.
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 *
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 * If `localStorage.noDeprecation = true` is set, then it is a no-op.
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 *
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 * If `localStorage.throwDeprecation = true` is set, then deprecated functions
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 * will throw an Error when invoked.
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 *
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 * If `localStorage.traceDeprecation = true` is set, then deprecated functions
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 * will invoke `console.trace()` instead of `console.error()`.
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 *
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 * @param {Function} fn - the function to deprecate
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 * @param {String} msg - the string to print to the console when `fn` is invoked
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 * @returns {Function} a new "deprecated" version of `fn`
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 * @api public
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 */
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function deprecate (fn, msg) {
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  if (config('noDeprecation')) {
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    return fn;
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  }
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  var warned = false;
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  function deprecated() {
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    if (!warned) {
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      if (config('throwDeprecation')) {
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        throw new Error(msg);
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      } else if (config('traceDeprecation')) {
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        console.trace(msg);
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      } else {
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        console.warn(msg);
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      }
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      warned = true;
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    }
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    return fn.apply(this, arguments);
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  }
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  return deprecated;
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}
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/**
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 * Checks `localStorage` for boolean values for the given `name`.
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 *
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 * @param {String} name
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 * @returns {Boolean}
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 * @api private
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 */
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function config (name) {
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  // accessing global.localStorage can trigger a DOMException in sandboxed iframes
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  try {
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    if (!global.localStorage) return false;
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  } catch (_) {
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    return false;
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  }
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  var val = global.localStorage[name];
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  if (null == val) return false;
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  return String(val).toLowerCase() === 'true';
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}
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