diff --git a/package.json b/package.json
index ef82aacb..664af0d9 100644
--- a/package.json
+++ b/package.json
@@ -61,6 +61,7 @@
     "typescript-eslint-parser": "18.0.0",
     "unicode-regex": "1.0.1",
     "unified": "6.1.6",
+    "vnopts": "1.0.2",
     "yaml": "ikatyang/yaml#a765c1ee16d6b8a5e715564645f2b85f7e04828b",
     "yaml-unist-parser": "ikatyang/yaml-unist-parser#cd4f73325b3fc02a6d17842d0d9cee0dfc729c9b"
   },
diff --git a/src/cli/constant.js b/src/cli/constant.js
index 5bb1db0a..de815c6c 100644
--- a/src/cli/constant.js
+++ b/src/cli/constant.js
@@ -85,7 +85,8 @@ const options = {
     category: coreOptions.CATEGORY_CONFIG,
     description:
       "Path to a Prettier configuration file (.prettierrc, package.json, prettier.config.js).",
-    oppositeDescription: "Do not look for a configuration file."
+    oppositeDescription: "Do not look for a configuration file.",
+    exception: value => value === false
   },
   "config-precedence": {
     type: "choice",
diff --git a/src/cli/util.js b/src/cli/util.js
index be6e5c3e..23c58bbe 100644
--- a/src/cli/util.js
+++ b/src/cli/util.js
@@ -848,12 +848,16 @@ function normalizeDetailedOptionMap(detailedOptionMap) {
 
 function createMinimistOptions(detailedOptions) {
   return {
+    // we use vnopts' AliasSchema to handle aliases for better error messages
+    alias: {},
     boolean: detailedOptions
       .filter(option => option.type === "boolean")
-      .map(option => option.name),
+      .map(option => [option.name].concat(option.alias || []))
+      .reduce((a, b) => a.concat(b)),
     string: detailedOptions
       .filter(option => option.type !== "boolean")
-      .map(option => option.name),
+      .map(option => [option.name].concat(option.alias || []))
+      .reduce((a, b) => a.concat(b)),
     default: detailedOptions
       .filter(option => !option.deprecated)
       .filter(
@@ -867,13 +871,6 @@ function createMinimistOptions(detailedOptions) {
         (current, option) =>
           Object.assign({ [option.name]: option.default }, current),
         {}
-      ),
-    alias: detailedOptions
-      .filter(option => option.alias !== undefined)
-      .reduce(
-        (current, option) =>
-          Object.assign({ [option.name]: option.alias }, current),
-        {}
       )
   };
 }
diff --git a/src/main/core-options.js b/src/main/core-options.js
index 688f45c7..39627106 100644
--- a/src/main/core-options.js
+++ b/src/main/core-options.js
@@ -66,7 +66,6 @@ const options = {
     since: "1.4.0",
     category: CATEGORY_SPECIAL,
     type: "path",
-    default: undefined,
     description:
       "Specify the input filepath. This will be used to do parser inference.",
     cliName: "stdin-filepath",
@@ -208,7 +207,10 @@ const options = {
     since: "0.0.0",
     category: CATEGORY_GLOBAL,
     type: "boolean",
-    default: false,
+    default: [
+      { since: "0.0.0", value: false },
+      { since: "1.15.0", value: undefined }
+    ],
     deprecated: "0.0.10",
     description: "Use flow parser.",
     redirect: { option: "parser", value: "flow" },
diff --git a/src/main/options-descriptor.js b/src/main/options-descriptor.js
deleted file mode 100644
index 8dc53ef7..00000000
--- a/src/main/options-descriptor.js
+++ /dev/null
@@ -1,22 +0,0 @@
-"use strict";
-
-function apiDescriptor(name, value) {
-  return arguments.length === 1
-    ? JSON.stringify(name)
-    : `\`{ ${apiDescriptor(name)}: ${JSON.stringify(value)} }\``;
-}
-
-function cliDescriptor(name, value) {
-  return value === false
-    ? `\`--no-${name}\``
-    : value === true || arguments.length === 1
-      ? `\`--${name}\``
-      : value === ""
-        ? `\`--${name}\` without an argument`
-        : `\`--${name}=${value}\``;
-}
-
-module.exports = {
-  apiDescriptor,
-  cliDescriptor
-};
diff --git a/src/main/options-normalizer.js b/src/main/options-normalizer.js
index 686d7353..ddec7663 100644
--- a/src/main/options-normalizer.js
+++ b/src/main/options-normalizer.js
@@ -1,152 +1,143 @@
 "use strict";
 
-const leven = require("leven");
-const validator = require("./options-validator");
-const descriptors = require("./options-descriptor");
+const vnopts = require("vnopts");
 
-function normalizeOptions(options, optionInfos, opts) {
-  opts = opts || {};
-  const logger =
-    opts.logger === false
-      ? { warn() {} }
-      : opts.logger !== undefined
-        ? opts.logger
-        : console;
-  const descriptor = opts.descriptor || descriptors.apiDescriptor;
-  const passThrough = opts.passThrough || [];
+const cliDescriptor = {
+  key: key => (key.length === 1 ? `-${key}` : `--${key}`),
+  value: value => vnopts.apiDescriptor.value(value),
+  pair: ({ key, value }) =>
+    value === false
+      ? `--no-${key}`
+      : value === true
+        ? cliDescriptor.key(key)
+        : value === ""
+          ? `${cliDescriptor.key(key)} without an argument`
+          : `${cliDescriptor.key(key)}=${value}`
+};
 
-  const optionInfoMap = optionInfos.reduce(
-    (reduced, optionInfo) =>
-      Object.assign(reduced, { [optionInfo.name]: optionInfo }),
-    {}
-  );
-  const normalizedOptions = Object.keys(options).reduce((newOptions, key) => {
-    const optionInfo = optionInfoMap[key];
+function normalizeOptions(
+  options,
+  optionInfos,
+  { logger, isCLI = false, passThrough = false } = {}
+) {
+  const unknown = !passThrough
+    ? vnopts.levenUnknownHandler
+    : Array.isArray(passThrough)
+      ? (key, value) =>
+          passThrough.indexOf(key) === -1 ? undefined : { [key]: value }
+      : (key, value) => ({ [key]: value });
 
-    let optionName = key;
-    let optionValue = options[key];
-
-    if (!optionInfo) {
-      if (passThrough === true || passThrough.indexOf(optionName) !== -1) {
-        newOptions[optionName] = optionValue;
-      } else {
-        logger.warn(
-          createUnknownOptionMessage(
-            optionName,
-            optionValue,
-            optionInfos,
-            descriptor
-          )
-        );
-      }
-      return newOptions;
-    }
-
-    if (!optionInfo.deprecated) {
-      optionValue = normalizeOption(optionValue, optionInfo);
-    } else if (typeof optionInfo.redirect === "string") {
-      logger.warn(createRedirectOptionMessage(optionInfo, descriptor));
-      optionName = optionInfo.redirect;
-    } else if (optionValue) {
-      logger.warn(createRedirectOptionMessage(optionInfo, descriptor));
-      optionValue = optionInfo.redirect.value;
-      optionName = optionInfo.redirect.option;
-    }
-
-    if (optionInfo.choices) {
-      const choiceInfo = optionInfo.choices.find(
-        choice => choice.value === optionValue
-      );
-      if (choiceInfo && choiceInfo.deprecated) {
-        logger.warn(
-          createRedirectChoiceMessage(optionInfo, choiceInfo, descriptor)
-        );
-        optionValue = choiceInfo.redirect;
-      }
-    }
-
-    if (optionInfo.array && !Array.isArray(optionValue)) {
-      optionValue = [optionValue];
-    }
-
-    if (optionValue !== optionInfo.default) {
-      validator.validateOption(optionValue, optionInfoMap[optionName], {
-        descriptor
-      });
-    }
-
-    newOptions[optionName] = optionValue;
-    return newOptions;
-  }, {});
-
-  return normalizedOptions;
+  const descriptor = isCLI ? cliDescriptor : vnopts.apiDescriptor;
+  const schemas = optionInfosToSchemas(optionInfos, { isCLI });
+  return vnopts.normalize(options, schemas, { logger, unknown, descriptor });
 }
 
-function normalizeOption(option, optionInfo) {
-  return optionInfo.type === "int" ? Number(option) : option;
-}
+function optionInfosToSchemas(optionInfos, { isCLI }) {
+  const schemas = [];
 
-function createUnknownOptionMessage(key, value, optionInfos, descriptor) {
-  const messages = [`Ignored unknown option ${descriptor(key, value)}.`];
-
-  const suggestedOptionInfo = optionInfos.find(
-    optionInfo => leven(optionInfo.name, key) < 3
-  );
-  if (suggestedOptionInfo) {
-    messages.push(`Did you mean ${JSON.stringify(suggestedOptionInfo.name)}?`);
+  if (isCLI) {
+    schemas.push(vnopts.AnySchema.create({ name: "_" }));
   }
 
-  return messages.join(" ");
+  for (const optionInfo of optionInfos) {
+    schemas.push(optionInfoToSchema(optionInfo, { isCLI }));
+
+    if (optionInfo.alias && isCLI) {
+      schemas.push(
+        vnopts.AliasSchema.create({
+          name: optionInfo.alias,
+          sourceName: optionInfo.name
+        })
+      );
+    }
+  }
+
+  return schemas;
 }
 
-function createRedirectOptionMessage(optionInfo, descriptor) {
-  return `${descriptor(
-    optionInfo.name
-  )} is deprecated. Prettier now treats it as ${
-    typeof optionInfo.redirect === "string"
-      ? descriptor(optionInfo.redirect)
-      : descriptor(optionInfo.redirect.option, optionInfo.redirect.value)
-  }.`;
-}
+function optionInfoToSchema(optionInfo, { isCLI }) {
+  let SchemaConstructor;
+  const parameters = { name: optionInfo.name };
+  const handlers = {};
 
-function createRedirectChoiceMessage(optionInfo, choiceInfo, descriptor) {
-  return `${descriptor(
-    optionInfo.name,
-    choiceInfo.value
-  )} is deprecated. Prettier now treats it as ${descriptor(
-    optionInfo.name,
-    choiceInfo.redirect
-  )}.`;
+  switch (optionInfo.type) {
+    case "int":
+      SchemaConstructor = vnopts.IntegerSchema;
+      if (isCLI) {
+        parameters.preprocess = value => Number(value);
+      }
+      break;
+    case "choice":
+      SchemaConstructor = vnopts.ChoiceSchema;
+      parameters.choices = optionInfo.choices.map(
+        choiceInfo =>
+          typeof choiceInfo === "object" && choiceInfo.redirect
+            ? Object.assign({}, choiceInfo, {
+                redirect: {
+                  to: { key: optionInfo.name, value: choiceInfo.redirect }
+                }
+              })
+            : choiceInfo
+      );
+      break;
+    case "boolean":
+      SchemaConstructor = vnopts.BooleanSchema;
+      break;
+    case "flag":
+    case "path":
+      SchemaConstructor = vnopts.StringSchema;
+      break;
+    default:
+      throw new Error(`Unexpected type ${optionInfo.type}`);
+  }
+
+  if (optionInfo.exception) {
+    parameters.validate = (value, schema, utils) => {
+      return optionInfo.exception(value) || schema.validate(value, utils);
+    };
+  } else {
+    parameters.validate = (value, schema, utils) => {
+      return value === undefined || schema.validate(value, utils);
+    };
+  }
+
+  if (optionInfo.redirect) {
+    handlers.redirect = value =>
+      !value
+        ? undefined
+        : {
+            to: {
+              key: optionInfo.redirect.option,
+              value: optionInfo.redirect.value
+            }
+          };
+  }
+
+  if (optionInfo.deprecated) {
+    handlers.deprecated = true;
+  }
+
+  return optionInfo.array
+    ? vnopts.ArraySchema.create(
+        Object.assign(
+          isCLI ? { preprocess: v => [].concat(v) } : {},
+          handlers,
+          { valueSchema: SchemaConstructor.create(parameters) }
+        )
+      )
+    : SchemaConstructor.create(Object.assign({}, parameters, handlers));
 }
 
 function normalizeApiOptions(options, optionInfos, opts) {
-  return normalizeOptions(
-    options,
-    optionInfos,
-    Object.assign({ descriptor: descriptors.apiDescriptor }, opts)
-  );
+  return normalizeOptions(options, optionInfos, opts);
 }
 
 function normalizeCliOptions(options, optionInfos, opts) {
-  const args = options["_"] || [];
-
-  const newOptions = normalizeOptions(
-    Object.keys(options).reduce(
-      (reduced, key) =>
-        Object.assign(
-          reduced,
-          key.length === 1 // omit alias
-            ? null
-            : { [key]: options[key] }
-        ),
-      {}
-    ),
+  return normalizeOptions(
+    options,
     optionInfos,
-    Object.assign({ descriptor: descriptors.cliDescriptor }, opts)
+    Object.assign({ isCLI: true }, opts)
   );
-  newOptions["_"] = args;
-
-  return newOptions;
 }
 
 module.exports = {
diff --git a/src/main/options-validator.js b/src/main/options-validator.js
deleted file mode 100644
index 7608c4b7..00000000
--- a/src/main/options-validator.js
+++ /dev/null
@@ -1,81 +0,0 @@
-"use strict";
-
-const descriptors = require("./options-descriptor");
-
-function validateOption(value, optionInfo, opts) {
-  opts = opts || {};
-  const descriptor = opts.descriptor || descriptors.apiDescriptor;
-
-  if (
-    typeof optionInfo.exception === "function" &&
-    optionInfo.exception(value)
-  ) {
-    return;
-  }
-
-  try {
-    validateOptionType(value, optionInfo);
-  } catch (error) {
-    throw new Error(
-      `Invalid \`${descriptor(optionInfo.name)}\` value. ${
-        error.message
-      }, but received \`${JSON.stringify(value)}\`.`
-    );
-  }
-}
-
-function validateOptionType(value, optionInfo) {
-  if (optionInfo.array) {
-    if (!Array.isArray(value)) {
-      throw new Error(`Expected an array`);
-    }
-    value.forEach(v =>
-      validateOptionType(v, Object.assign({}, optionInfo, { array: false }))
-    );
-  } else {
-    switch (optionInfo.type) {
-      case "int":
-        validateIntOption(value);
-        break;
-      case "boolean":
-        validateBooleanOption(value);
-        break;
-      case "choice":
-        validateChoiceOption(value, optionInfo.choices);
-        break;
-    }
-  }
-}
-
-function validateBooleanOption(value) {
-  if (typeof value !== "boolean") {
-    throw new Error(`Expected a boolean`);
-  }
-}
-
-function validateIntOption(value) {
-  if (
-    !(
-      typeof value === "number" &&
-      Math.floor(value) === value &&
-      value >= 0 &&
-      value !== Infinity
-    )
-  ) {
-    throw new Error(`Expected an integer`);
-  }
-}
-
-function validateChoiceOption(value, choiceInfos) {
-  if (!choiceInfos.some(choiceInfo => choiceInfo.value === value)) {
-    const choices = choiceInfos
-      .filter(choiceInfo => !choiceInfo.deprecated)
-      .map(choiceInfo => JSON.stringify(choiceInfo.value))
-      .sort();
-    const head = choices.slice(0, -2);
-    const tail = choices.slice(-2);
-    throw new Error(`Expected ${head.concat(tail.join(" or ")).join(", ")}`);
-  }
-}
-
-module.exports = { validateOption };
diff --git a/src/main/options.js b/src/main/options.js
index 302f0c8b..b1f678ef 100644
--- a/src/main/options.js
+++ b/src/main/options.js
@@ -27,7 +27,9 @@ function normalize(options, opts) {
   }).options;
   const defaults = supportOptions.reduce(
     (reduced, optionInfo) =>
-      Object.assign(reduced, { [optionInfo.name]: optionInfo.default }),
+      optionInfo.default !== undefined
+        ? Object.assign(reduced, { [optionInfo.name]: optionInfo.default })
+        : reduced,
     Object.assign({}, hiddenDefaults)
   );
 
diff --git a/tests_integration/__tests__/__snapshots__/arg-parsing.js.snap b/tests_integration/__tests__/__snapshots__/arg-parsing.js.snap
index b1486adf..2ecb96e9 100644
--- a/tests_integration/__tests__/__snapshots__/arg-parsing.js.snap
+++ b/tests_integration/__tests__/__snapshots__/arg-parsing.js.snap
@@ -10,7 +10,7 @@ exports[`boolean flags do not swallow the next argument (stdout) 1`] = `
 exports[`boolean flags do not swallow the next argument (write) 1`] = `Array []`;
 
 exports[`deprecated option values are warned (stderr) 1`] = `
-"[warn] \`--trailing-comma\` without an argument is deprecated. Prettier now treats it as \`--trailing-comma=es5\`.
+"[warn] --trailing-comma without an argument is deprecated; we now treat it as --trailing-comma=es5.
 "
 `;
 
@@ -22,7 +22,7 @@ exports[`deprecated option values are warned (stdout) 1`] = `
 exports[`deprecated option values are warned (write) 1`] = `Array []`;
 
 exports[`deprecated options are warned (stderr) 1`] = `
-"[warn] \`--flow-parser\` is deprecated. Prettier now treats it as \`--parser=flow\`.
+"[warn] --flow-parser is deprecated; we now treat it as --parser=flow.
 "
 `;
 
@@ -43,7 +43,7 @@ exports[`negated options work (stdout) 1`] = `
 exports[`negated options work (write) 1`] = `Array []`;
 
 exports[`unknown negated options are warned (stderr) 1`] = `
-"[warn] Ignored unknown option \`--no-unknown\`.
+"[warn] Ignored unknown option --no-unknown.
 "
 `;
 
@@ -55,7 +55,7 @@ exports[`unknown negated options are warned (stdout) 1`] = `
 exports[`unknown negated options are warned (write) 1`] = `Array []`;
 
 exports[`unknown options are warned (stderr) 1`] = `
-"[warn] Ignored unknown option \`--unknown\`.
+"[warn] Ignored unknown option --unknown.
 "
 `;
 
diff --git a/tests_integration/__tests__/__snapshots__/config-invalid.js.snap b/tests_integration/__tests__/__snapshots__/config-invalid.js.snap
index e3dbb858..90e9857c 100644
--- a/tests_integration/__tests__/__snapshots__/config-invalid.js.snap
+++ b/tests_integration/__tests__/__snapshots__/config-invalid.js.snap
@@ -1,7 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`show warning with kebab-case option key (stderr) 1`] = `
-"[warn] Ignored unknown option \`{ \\"print-width\\": 3 }\`. Did you mean \\"printWidth\\"?
+"[warn] Ignored unknown option { \\"print-width\\": 3 }. Did you mean printWidth?
 "
 `;
 
@@ -10,7 +10,7 @@ exports[`show warning with kebab-case option key (stdout) 1`] = `""`;
 exports[`show warning with kebab-case option key (write) 1`] = `Array []`;
 
 exports[`show warning with unknown option (stderr) 1`] = `
-"[warn] Ignored unknown option \`{ \\"hello\\": \\"world\\" }\`.
+"[warn] Ignored unknown option { hello: \\"world\\" }.
 "
 `;
 
@@ -37,7 +37,7 @@ exports[`throw error with invalid config format (stdout) 1`] = `""`;
 exports[`throw error with invalid config format (write) 1`] = `Array []`;
 
 exports[`throw error with invalid config option (int) (stderr) 1`] = `
-"[error] Invalid \`\\"tabWidth\\"\` value. Expected an integer, but received \`0.5\`.
+"[error] Invalid tabWidth value. Expected an integer, but received 0.5.
 "
 `;
 
@@ -46,7 +46,7 @@ exports[`throw error with invalid config option (int) (stdout) 1`] = `""`;
 exports[`throw error with invalid config option (int) (write) 1`] = `Array []`;
 
 exports[`throw error with invalid config option (trailingComma) (stderr) 1`] = `
-"[error] Invalid \`\\"trailingComma\\"\` value. Expected \\"all\\", \\"es5\\" or \\"none\\", but received \`\\"wow\\"\`.
+"[error] Invalid trailingComma value. Expected \\"all\\", \\"es5\\" or \\"none\\", but received \\"wow\\".
 "
 `;
 
@@ -55,7 +55,7 @@ exports[`throw error with invalid config option (trailingComma) (stdout) 1`] = `
 exports[`throw error with invalid config option (trailingComma) (write) 1`] = `Array []`;
 
 exports[`throw error with invalid config precedence option (configPrecedence) (stderr) 1`] = `
-"[error] Invalid \`\`--config-precedence\`\` value. Expected \\"cli-override\\", \\"file-override\\" or \\"prefer-file\\", but received \`\\"option/configPrecedence\\"\`.
+"[error] Invalid --config-precedence value. Expected \\"cli-override\\", \\"file-override\\" or \\"prefer-file\\", but received \\"option/configPrecedence\\".
 "
 `;
 
diff --git a/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap b/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap
index beb62c7a..5eda05a7 100644
--- a/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap
+++ b/tests_integration/__tests__/__snapshots__/deprecated-parser.js.snap
@@ -1,6 +1,6 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`API format with deprecated parser should work 1`] = `
-"\`{ \\"parser\\": \\"postcss\\" }\` is deprecated. Prettier now treats it as \`{ \\"parser\\": \\"css\\" }\`.
+"{ parser: \\"postcss\\" } is deprecated; we now treat it as { parser: \\"css\\" }.
 "
 `;
diff --git a/tests_integration/__tests__/__snapshots__/with-config-precedence.js.snap b/tests_integration/__tests__/__snapshots__/with-config-precedence.js.snap
index ce5002c6..c1a87149 100644
--- a/tests_integration/__tests__/__snapshots__/with-config-precedence.js.snap
+++ b/tests_integration/__tests__/__snapshots__/with-config-precedence.js.snap
@@ -252,7 +252,7 @@ function rcYaml() {
 exports[`CLI overrides take precedence without --config-precedence (write) 1`] = `Array []`;
 
 exports[`CLI validate options with --config-precedence cli-override (stderr) 1`] = `
-"[error] Invalid \`\\"printWidth\\"\` value. Expected an integer, but received \`0.5\`.
+"[error] Invalid printWidth value. Expected an integer, but received 0.5.
 "
 `;
 
@@ -261,7 +261,7 @@ exports[`CLI validate options with --config-precedence cli-override (stdout) 1`]
 exports[`CLI validate options with --config-precedence cli-override (write) 1`] = `Array []`;
 
 exports[`CLI validate options with --config-precedence file-override (stderr) 1`] = `
-"[error] Invalid \`\\"printWidth\\"\` value. Expected an integer, but received \`0.5\`.
+"[error] Invalid printWidth value. Expected an integer, but received 0.5.
 "
 `;
 
@@ -270,7 +270,7 @@ exports[`CLI validate options with --config-precedence file-override (stdout) 1`
 exports[`CLI validate options with --config-precedence file-override (write) 1`] = `Array []`;
 
 exports[`CLI validate options with --config-precedence prefer-file (stderr) 1`] = `
-"[error] Invalid \`\\"printWidth\\"\` value. Expected an integer, but received \`0.5\`.
+"[error] Invalid printWidth value. Expected an integer, but received 0.5.
 "
 `;
 
diff --git a/yarn.lock b/yarn.lock
index 0edd7aee..feef2fe6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5658,6 +5658,10 @@ tslib@^1.8.0, tslib@^1.9.1:
   version "1.9.1"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.9.1.tgz#a5d1f0532a49221c87755cfcc89ca37197242ba7"
 
+tslib@^1.9.3:
+  version "1.9.3"
+  resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.9.3.tgz#d7e4dd79245d85428c4d7e4822a79917954ca286"
+
 tty-browserify@0.0.0:
   version "0.0.0"
   resolved "https://registry.yarnpkg.com/tty-browserify/-/tty-browserify-0.0.0.tgz#a157ba402da24e9bf957f9aa69d524eed42901a6"
@@ -5917,6 +5921,14 @@ vm-browserify@0.0.4:
   dependencies:
     indexof "0.0.1"
 
+vnopts@1.0.2:
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/vnopts/-/vnopts-1.0.2.tgz#f6a331473de0179d1679112cc090572b695202f7"
+  dependencies:
+    chalk "^2.4.1"
+    leven "^2.1.0"
+    tslib "^1.9.3"
+
 w3c-hr-time@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/w3c-hr-time/-/w3c-hr-time-1.0.1.tgz#82ac2bff63d950ea9e3189a58a65625fedf19045"