<h4 dir="auto">Describe the bug</h4>
<p dir="auto">The <code class="notranslate">params</code> values which i defined while creating a new instance are not part of the request.</p>
<h4 dir="auto">To Reproduce</h4>
<p dir="auto">I created a minimal example: <a href="https://jsfiddle.net/oqfract9" rel="nofollow">https://jsfiddle.net/oqfract9</a></p>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="const instance = axios.create({
  baseURL: 'https://jsonplaceholder.typicode.com/',
  timeout: 1000,
  params: {
    &quot;userId&quot;: &quot;1&quot;
  }
});

instance
.get(&quot;/posts&quot;)
.then(function (response) {
    console.log(response.data);
    console.log(response.status);
    console.log(response.statusText);
    console.log(response.headers);
    console.log(response.config);
  });"><pre class="notranslate"><span class="pl-k">const</span> <span class="pl-s1">instance</span> <span class="pl-c1">=</span> <span class="pl-s1">axios</span><span class="pl-kos">.</span><span class="pl-en">create</span><span class="pl-kos">(</span><span class="pl-kos">{</span>
  <span class="pl-c1">baseURL</span>: <span class="pl-s">'https://jsonplaceholder.typicode.com/'</span><span class="pl-kos">,</span>
  <span class="pl-c1">timeout</span>: <span class="pl-c1">1000</span><span class="pl-kos">,</span>
  <span class="pl-c1">params</span>: <span class="pl-kos">{</span>
    <span class="pl-s">"userId"</span>: <span class="pl-s">"1"</span>
  <span class="pl-kos">}</span>
<span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

<span class="pl-s1">instance</span>
<span class="pl-kos">.</span><span class="pl-en">get</span><span class="pl-kos">(</span><span class="pl-s">"/posts"</span><span class="pl-kos">)</span>
<span class="pl-kos">.</span><span class="pl-en">then</span><span class="pl-kos">(</span><span class="pl-k">function</span> <span class="pl-kos">(</span><span class="pl-s1">response</span><span class="pl-kos">)</span> <span class="pl-kos">{</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s1">response</span><span class="pl-kos">.</span><span class="pl-c1">data</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s1">response</span><span class="pl-kos">.</span><span class="pl-c1">status</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s1">response</span><span class="pl-kos">.</span><span class="pl-c1">statusText</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s1">response</span><span class="pl-kos">.</span><span class="pl-c1">headers</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s1">response</span><span class="pl-kos">.</span><span class="pl-c1">config</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
  <span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span></pre></div>
<h4 dir="auto">Expected behavior</h4>
<p dir="auto">I would expect that the <code class="notranslate">?userId=1</code> is part of the request.</p>
<h4 dir="auto">Environment</h4>
<ul dir="auto">
<li>Axios v0.19.2</li>
<li>Chrome v83.0.4103.106</li>
<li>Node.js v12.14.0</li>
<li>React v16.13.1</li>
</ul>
<h4 dir="auto">Additional context/Screenshots</h4>
<p dir="auto">I'm currently using the npm package, but it also doesn't work with CDN version.</p>
<p dir="auto"><strong>Describe the bug</strong></p>
<p dir="auto">Specific request params do not get merged with the instance default params.</p>
<p dir="auto"><strong>To Reproduce</strong></p>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="const instance = axios.create({
    baseURL: &quot;http://www.example.com&quot;,
    params: {
      q: &quot;question&quot;,
    }
  });"><pre class="notranslate"><span class="pl-k">const</span> <span class="pl-s1">instance</span> <span class="pl-c1">=</span> <span class="pl-s1">axios</span><span class="pl-kos">.</span><span class="pl-en">create</span><span class="pl-kos">(</span><span class="pl-kos">{</span>
    <span class="pl-c1">baseURL</span>: <span class="pl-s">"http://www.example.com"</span><span class="pl-kos">,</span>
    <span class="pl-c1">params</span>: <span class="pl-kos">{</span>
      <span class="pl-c1">q</span>: <span class="pl-s">"question"</span><span class="pl-kos">,</span>
    <span class="pl-kos">}</span>
  <span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span></pre></div>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="instance.get(&quot;/page&quot;, 
  { 
    params: { 
      page: 2 
    }
  }
)"><pre class="notranslate"><span class="pl-s1">instance</span><span class="pl-kos">.</span><span class="pl-en">get</span><span class="pl-kos">(</span><span class="pl-s">"/page"</span><span class="pl-kos">,</span> 
  <span class="pl-kos">{</span> 
    <span class="pl-c1">params</span>: <span class="pl-kos">{</span> 
      <span class="pl-c1">page</span>: <span class="pl-c1">2</span> 
    <span class="pl-kos">}</span>
  <span class="pl-kos">}</span>
<span class="pl-kos">)</span></pre></div>
<p dir="auto">What happens is that the request param object overrides the instance default param object. The instance no longer has a query param of <code class="notranslate">q</code>.</p>
<p dir="auto"><strong>Expected behavior</strong></p>
<p dir="auto">According to the docs, all configuration options are <em>merged</em>. <a href="https://github.com/axios/axios#instance-methods">https://github.com/axios/axios#instance-methods</a></p>
<p dir="auto">I expected request to contain both <code class="notranslate">q</code> and <code class="notranslate">page</code> params. This is also how it was working in version 0.18.0, which is how I noticed.</p>
<p dir="auto"><strong>Environment:</strong></p>
<ul dir="auto">
<li>Axios Version: 0.19.0</li>
<li>OS: 10.14.5 (18F132)</li>
<li>Browser: Node Express, and Chrome</li>
<li>Browser: Node 10.15.0, Chrome Version 74.0.3729.169 (Official Build) (64-bit)</li>
</ul>